Besides Kubo news, there are also the continuous rumors about Sket Dance author, Shimabukuro or Amano coming back soon. Heck, Nurarihyon no author is already back.
I can imagine totally Shonen Jump in 2020-2021 with a lot of its publications being by 2000s authors (we also have Inagaki already). Which makes me wonder...
What about 90s authors? Why are they all mising? Prince of Tennis author I imagine he continues with his endless sequel. But what about Hoshi Engi author? NuBe author? Ninku author? Yu-gi-oh author? (Yeah, we got The Comiq for 7 weeks but...).
So some of the 1995 onwards WSJ manga that lasted at least a year:
Naruto- Masashi Kishimoto (Samurai 8)
The Prince of Tennis- Takeshi Konomi (The New Prince of Tennis ongoing)
Hikaru no Go- Yumi Hotta (did Yuuto for WSJ but flopped, nothing since then) and Takeshi Obata (Platinum End)
Rising Impact- Nakaba Suzuki (moved to Kodansha for The Seven Deadly Sins)
Shaman King- Hiroyuki Takei (moved to Kodansha for Shaman King spinoffs)
Whistle- Daisuke Higuchi (moved to Shogakukan for Whistle W!)
Rookies- Masanori Morita (did Beshari Gurashi which flopped and is nowhere to be heard from since then)
Meiryotei Gotoseijuro- Hajime Kazu (Luck Stealer which ended in 2012)
Seikimatsu Leader-den Takeshi!- Mitsutoshi Shimabukuro (Toriko and oneshots after that but still nothing)
I''s-Masakazu Katsura (Zetman which ended in 2014)
Hanasaka Tenshi Tenten-kun-Kazumata Oguri (now working on Gag manga in Saikyo Jump)
Yu-Gi-Oh!- Kazuki Takahashi (The Comiq, and from the comments he made I doubt he will return to any sort of regular weekly serialization at least)
Hoshin Engi- Ryu Fujisaki (Ginga Eiyuu Densetsu ongoing)
Makuhari- Yasuaki Kita (moved to Kodansha to work on Kenka Kagyou)
Wild Half- Asami Yuuko (did Romancers in 1999 which bombed and is nowhere to be heard from since then)