If you are at all interested in the state of Jump serializations over the years I consider this will be an interesting (Though lenghty...Perhaps too lenghty read), so thanks for reading.
I counted the total number of series Jump has ever published (692 as of now) and there was a clear tendency towards publishing less and less new series, but I'm pretty sure that from 68 to the 80s Jump published around 180 series, which if we take out the series published during the 68s, 69 period would be I assume around 150 series, this number was constantly lower and lower.
68,69: 26 AKA the 4 manga introductory line up & other manga that were slowly but surely added.
70s: 157
80s: 152
90s: 128
00s: 115
10s: 114
(Keep in mind this is the decade -2010s if anyone is reading this in the year 2053 or something lol- were Jump started putting spinoff mangas like the Naruto side story, Boruto and the new Dr.Stone spin-off in the main magazine... So if we take those out is 111
new serializations... IIRC the only other manga whose manga had been released again in Jump was Captain Tsubasa but that was truly a sequel to Captain Tsuabsa... I guess Boruto is a sequel to Naruto... In a sense.. But you get my point.)
Anyway, there's a clear trend to less new serializations, from 157 in the 70s to 114 (111 IMO, but whatever) that's almost a 30% decline in new serializations.
To me the reason is clear, JUMP serializations now tend to be longer and longer, and they kind of let some series "live" longer even though their sales aren't that impressive, think series like Beelzebub, Black Clover, heck even Toriko to an extenct... They lived longer, while series like Shaman King or even Saint Seiya were cancelled.
A good example of this would be Beelzebub with exactly the same number of volumes as Saint Seiya (28 Tankobon), Beelzebub sold 8'066,000 (Last updated May 2015 according to
EasyLove's Top 125 WSJ manga youtube video while Saint Seiya sold 25'000,000 in its 28 tankobon run...
NOW you may be saying but wait, Saint Seiya's run was in 1986 so it has had waaaaaaaay more time to sell manga, and yes you would be right, but I also found this
comipress article from 2006 which still has Saint Seiya at 25 million volumes... So it's pretty damn weird that from 2006 to 2014 (The time in EasyLove's video) Saint Seiya didn't sell an extra million volumes? That's where Netflix PR release came to the rescue, informating us that SS has sold 35million volumes (Perhaps worldwide? IDK).
The point stands that even then Saint Seiya probably was a half a million seller (and I'm being very conservative, I don't think the series sold 14'000,000 in its heyday and had super long legs to eventually sell 35million, that's not how things like this work, for example Slam Dunk had 120million recorded in 2006 and as of 2017 it has sold 170 million volumes, btw this is before the new "Refurbished" edition which probably put another 10 million to Slam Dunk's numbers)
So Saint Seiya a half a million volume seller at its time and it was axed by JUMP... Seriously, what other Jump manga of recent years were half-million sellers and were cancelled?
Other excellent example to compare Saint Seiya to is Toriko, a series which received a HUGE boost by the editorial department, a long anime by Toei and admitedly was a great seller, according to this
post Toriko had surpassed 20 million sales by its 30th volume, which is pretty much on spot the sales Saint Seiya had in my estimate of sales, and yet Toriko was allowed to "live" for an extra 4 years of serialization while Saint Seiya was cancelled (BTW this was confirmed by its author, Masami Kurumada himself. He always stated he wanted to create a last Zeus arc but wasn't allowed by JUMP) so there's definetly a bias by the Jump editorial department to be more lax with 'medium-tier' popular series (Medium tier I'd say are series that reach half a million per volume at some point of their runs and then steadily decline, think Toriko against a super popular manga like Assasination Classroom which is a great hit.
There's also the case of Shaman King, which was ultra weird, like there was this
petition apparently (Which I remember I also read in one of Shaman King's latest volumes extra notes) in which Shueisha wanted to know how many fans would buy the volumes....
It's just too weird because, like it just doesn't make any sense, I can not fathom SK selling so low to Shueisha not even considering printing its last volume (Especially when you consider that it received a Kanzenban reprint later with a new ending).
I tend to diverge while I write long posts like this, so excuse me lol. But the point still stands, series from the past were cancelled when they were selling way better than what most titles that Jump let's continue nowadays.
And that's basically the reason we are seeing less and less new serializations by the decade, Jump being more lax with some "good sellers that are in decline" while some ultra popular long titles were running amok in the magazine (Just think there was a time not too long ago with Kochikame, Gintama, Naruto, BLEACH,One Piece, Hunter x Hunter (Kinda) and even
Jojo Steel Ball Run running all at the same time, 7 titles that would end up surpassing 70 volumes, yeah that was in the year 2004 and all those series did run together for a short period of time (Until SBR changed magazines)...
To add insult to injury Prince of Tennis, Reborn and Eyeshield 21 (And D-Gray Man which I think if it weren't for Katsura's illness would have been a seller in the same levels of at least BLEACH, this is coming from someone that didn't actually enjoy D-Gray Man that much, I'm in no way a huge fan or anything lol, but it did sell like crazy).
So yeah, in 2004 you could open a Jump magazine that had Kochikame, Gintama, Naruto, BLEACH, One Piece, Hunter x Hunter, Steel Ball Run (Jojo), Prince of Tennis, Reborn and Eyeshield 21 in its lineup which is just crazy, and that's probably why Steel Ball Run was moved to another magazine, because quite frankly half the TOC was occupied by series that would end up becoming some of Jump's biggest properties.
Heck, take a look at these TOCs from 2004. (BTW this is the issue where BLACK CAT ends lol, but I put it because it had Black Cat in it)
Volume 29 (28-6-2004)
Naruto (Absent in ranked issue)
1. Death Note
2. One Piece
3. Bobobo-bo Bo-bobo
4. Eyeshield 21
5. Bleach
6. Buso Renkin
7. Prince of Tennis
8. Gintama
9. Gedo the Unidentified Mysterious Boy
10. Ichigo 100%
11. Kochikame
12. Shaman King
Cover & Lead Colour Page: Steel Ball Run (Resume)
Colour Page: Katekyo Hitman Reborn!
Colour Page: Black Cat (END)
Absent: Mr. Fullswing and HunterXHunter
For some reason is not mentioned even though it was being run in Jump at the time: D-Gray Man
The least succesful manga in this lineup were Gedo (created by Hell Teacher nube mangaka), and to a lesser exctent Mr. Fullswing (Which ran for like 23 volumes IIRC, but sadly never got an anime...). The next "less succesful" (Again, if you can call it that) was Buso Renkin by Watsuki AKA Ruroken's mangaka, which ran for like 10 volumes but ended up having an anime adaptation (After it ended, I think).
In this 19 manga lineup 17 series ended up having an anime adaptation.
In hindsight that's perhaps why Shaman King had to be cut, SBR had to move to another magazine, and also a promising series that ended up getting an anime after they finished their run would end up "cancelled" (Black Cat and Buso Renkin), Jump simply was too stuffed at that point. And I can honestly say I'd be hard pressed to cancel any of the other series in the magazine that were running at the time.
Comparing it to other lineups for example the lineup of 1986 issues 6: 11 out of 17 received an anime adaptation
Or the lineup of 2016 issues 52: 11 out of 17 receive an anime adaptation
So.. What exactly does this mean? There's a huge difference in the rotation of new series, especially when you consider that the average popular series of the 86 lineup had around 30 volumes while pior to the 2016's (Let's say in 2010, back when Toriko, Reborn, BLEACH, Gintama and other titles that ended up being longer than 40 volumes were running (I didn't count Kochikame because... Kochikame is just an outlier that would probably screw the averages too much)
Anyway... the average series running in 2010 Jump was 21 volumes (I summed them up rather quickly and ended up with around 400 volumes, counting One Piece has having 50 volumes at the time, Naruto having 40 volumes -rounded up numbers not exact-.) So 400 volumes divided by the 19 manga running in the line up gives us 21 volumes average.
Now, summing the total volumes of today's line up it summed to 290 volumes (It's probably lower but it was a quick sum rounding up what I remember each series more or less has in volumes) divided by 20 is 14.5 per volume BUT remember One Piece is 90 volumes long (I know is longer but again, I rounded things), if we take out the outlier One Piece and divide the remaining 19 manga by the remaining 200 volumes it's an average of 10 per volume!
But what exactly does this mean?? What's the point of this super long post?
Jump is at a crossroad, at a point in its life in which it hasn't been in forever (too lazy to check but I'd say... maybe it hasn't been like this since the mid 80s)
Only 4 (5 if you count HxH) of its serialized manga are longer than 20 volumes long. Compared to 2010s line up with 11(!) at the time manga that had 20 volumes or more. (Again, in hindsight if Shaman King was cancelled because 17 out of 19 manga were uber popular in its time, then this is the opposite for Black Clover which let's just admit... It's not a huge seller, and is alive in the magazine because well.. The magazine doesn't currently have that many huge -or super long- series).
And this, IMO, is what happens when you depend on letting manga continue for too much time without giving new series (AKA serializations) enough opportunities, think of it this way, the long running series that started back in say 2004, or 2001 like BLEACH ran their course (There's so much you can over-extent a series until it just becomes lame)...
BUT at the same time I see this as an opportunity for JUMP because it can rebuilt its lineup and have 3 battle shonen pillars like it used to (I guess they are already One Piece, My Hero Academia and Kimetsu no Yaiba) although they aren't/won't be anywhere near the old Big 3 (E.g. BLEACH had sold 30million back when it only had 22 volumes,
source comipress) while right now My Hero Academia has sold 24 million with 24 volumes and IMO it already reached its peak probably...
As I said I don't think Jump is lacking in any other kind of manga, just the pillar battle shonen manga that have been absent since BLEACH/Naruto
. Popular sport manga have appeared (Kuroko/Haiykuu) as so 'other genre' kind of manga like Bakuman, Assclass and Promised neverland and then Ecchi/Romcom haven't been a problem either, although it seems Jump lost the "Romcom" war because Magazine has the manga about the quintuplets (which I can only assume is a bigger seller than Jump romcoms?)...
Jump has never been the magazine for mystery manga (like the other magazines have Conan and Kindaichi Shounen no Jikenbo, I guess the latest detective-esque popular Jump title was Neuro (IIRC?) and Death Note (I said detective-esque lol)..
And Jump has also got its fair share of comedy manga over the year with Gintama and Saiki recently ending, BUT that's one genre that's currently missing in the magazine (I tink? I don't really pay much attention to comedy manga).
http://pharaodopazoplusni.blogspot.com/p/weekly-shonen-jump-pure-rankings-2015.html
Extra notes:
*Fun fact the very first manga in Jump (Kujira Daigo, which was the front color page, so I can only assume what the editors wanted to represent JUMP) was a flop that only lasted for like 10 chapters (Nice way to make an statement of being the manga magazine to cut manga that didn't sell/didn't rank well without any mercy lol, though maybe every manga magazine was like that at thetime?)
*Don't judge me lol, I'm a nerd for counting stuff and analysing trends stuff like that.