Launching gag manga when you're adopting a "spread fire" mentality makes sense. With so many series ending, Jump can't be "conservative" with how they arrange picks, but they also have to be careful to not overwhelm readers and cause cannibalisation. Gag manga by their nature are low selling, disposable casual reads that are useful for weekly readers and can be easily discarded. It's worth remembering that most of the "pure" gag manga launched aren't from unknown or little tested authors, Hatomune had a strong following on Jump+, Hasegawa was in Jump for over a year with Spring Weapon, Miyazaki did the TPN 4-koma, and Nakama was active and decently successful in Jump for a good four years of publication. Essentially these exist as a rotating door of casual reader devices which Jump can use while it tries to build a roster of actually stable titles, simple as that.
On the part of "why no spokon", I ask again, what evidence do you have Jump has some? While I know it seems slightly sacrilegious for Jump to lack a member of the genre, the simple reality is that sports manga is a very tough nut to crack in the modern era because there's simply so many iconic titles and so little manoeuvrability that it's very much a challenge to even stand out, let alone be accepted by the readerbase. So I imagine relatively little will happen to change the situation.
new serialization round
Gotou's fav manga: Fullmetal Alchemist
Matsuura's fav manga: Trigun
Kazu Kakazu fav manga: Tegamibachi, Mushishi, Natsume Yuujinchou
Well, Kakazu's favs are...interesting, to say the least. Wonder if we'll see that taste reflected in his work.