Well, there are titles that get a lot from Jump and they don't deserve it (Toriko), and titles that they don't get love from Jump and they deserve it (Hinomaru).
I don't think that's fair tbh. Hinomaru should've been cancelled years ago based on its performance, let alone continuing to get promotion in the form of many colour pages, and even an anime. It's still one of the series that gets the most colour pages each year, and in one of its first years, it got more than pretty much everything else. Surely it's one of, if not the worst performing Jump series to ever get an anime. It's been promoted at sumo tournaments since it began too. Yes, the anime doesn't seem like it'll justify the series' quality, but it
more than justifies its performance, regardless of how it turns out. I'd argue it's even too much. They've really done all they can for it and more. They've promoted the hell out of it, and it's failed to deliver every single time, without exception. You can't blame investors for thinking an anime won't change anything. The fact it hasn't caught on is simply due to the nature of the series, and I don't think any amount of backing from Jump or anyone could have/is going to change that.
On another note though, I do think Toriko deserved what it got if we're talking quality. For OP fans, it was exciting as hell to be so reminiscent of it, and it delivered for the most part in those first few years. In my entire manga-reading life, discovering Toriko for the first time definitely stands out as a highlight. I truly think it was a something special. Hell, it's pretty much the only adventure series we've had in Jump since OP that even got close to it that didn't disappoint. Its success just wasn't reflective of its backing, but I don't think many series could have delivered had they got the same either. To add to that, despite all the bad things people have to say about the anime, I personally think the way it was presented certainly added to that sense of wonder, and I actually don't think a more accurate adaption would've resulted in the manga performing better than it did.
Some random stuff I was thinking.
Act-age and Jujutsu are already succesful in Jump. However, at chapter 20, BokuBen and Dr.Stone were way more popular and had consolidated Edited Mangas. Dr.Stone I can understand since is Eyeshield21 author + Boichi, but BokuBen was a newbie.
So, I think the reason Jujutsu and Act-age are still so unknown is Viz.
95% of readers probably don't even know who Viz is, let's be honest. Personally, I think it's a multitude of factors - mainly, success in Japan right off the bat (which also influences when and what Manga Editors pick a series up, something that is incredibly important for more niche series), and obviously mainstream western appeal.
Anything that's had a slow start performance-wise usually gets screwed over in Edited Mangas, and a slow start performance-wise generally means they just had a poor first few chapters in general, which turns off Manga Editors. Then obviously anything done by larger groups will get exposed to a larger audience, and this is even more true if they're picked up from chapter 1 (which is mostly down to how exciting the preview for a series looks). Plus obviously the promotion for the 6-round helped, since it hyped up Manga Editors enough to do the first chapters for them all straight away, which directly influenced the readers down the line. And as for what was said about Red Sprite and Demon's Plan which lacked that promotion, I think they had that Western appeal, and they replaced a bunch of big-name series, so Manga Editors had the room to pick up new series too.
Both Bokuben and Stone also have mainstream Western appeal in pretty much every way too, so it's hard to make comparisons. Act-age certainly can't be compared to Bokuben, not being a romance, and having iffy art, it's a niche series no matter how you shake it. Jujutsu had one of the most generic and unexciting starts possible, plus it also has the art issue. Western readers are pretty critical about art, and it normally takes longer for series like that to take off. At first glance, what takes your interest more? An exorcism manga with nothing else noteworthy to say about it, or a post-apocalyptic manga about science where everyone is turned to stone?
And finally to add to all this, Bokuben was very much riding off the fact it was the 'new' Nisekoi, and Stone had established mangaka working on it, so you could also argue that both series had a helping hand from chapter 1.
.
