I would say the main thing is.... even after the time skip we are getting all the BS oda can add.

They gained more knowledge in their field too(talking about nami, chopper, franky etc)... but that is useless plot now
Not his fult really. Jump has a lot of say over their artists work
After DBZ ended with Kid Buu and the Uub tournament, Jump needed 3 stories with mass advertisement all over the world to not lose popularity: Naruto, Bleach and One Piece
One Piece is at least as big in Japan as DBZ was and worldwide views are also great (DBZ is Brazil is way way way bigger still though)
I'm sure this dragging shit it not Oda's doing at all. Jump overlords are not gonna let this cash cow die.
Every single fucking arc we have a cutesy female for degens to fap to. Nami, Vivi, Robin, Shirahoshi, Rebecca, Monet, Viola, Smoothie, Reiju.
In wano we have Yamato.
There is always gonna be another ty, another hentai, another cool fruit, another power, another figurine.
ROGER USED KAMUSARI. LET'S MAKE AN ACTION FIGURE OUT OF THAT.
How many Gear 4 figurines variants we have?
One Piece is a billion dollars business. It's going on for at least 10 years minimum
Akira Toriyama wanted to end DBZ after Freeza. We still got fucking DBZ to this date with new chapters
If you come from the future and tell me we still get One Piece NEW GENERATION with Zoro's grand children conquering One Piece i'll fucking believe you