Maybe cuz each Arc is written for the new 16 year olds; it's not like it's aiming to change the formula to match growth of old readers.
1997 One Piece was written for those born around 1981,
2026 One Piece is written for those born around 2010,
At least that's the aim, regardless of successful or not, and it does contain few other stuff to attract wider range of readers & older fans,
But the core audience are youngsters, that's why the formula doesn't change,
In case you haven't noticed, go check the reaction of SHs when Luffy declared his Secret Dream, those almost 20 or older either found it weirdly shocking or hilarious & crazy, but Chopper who is 17 years old clearly loved it so much instantly, that scene alone summarizes everything about the goal of this Manga, it's simply the fantasy of a 16-17 year old Oda (Which happens to be when He started his job),
The Formula will never change.
1997 One Piece was written for those born around 1981,
2026 One Piece is written for those born around 2010,
At least that's the aim, regardless of successful or not, and it does contain few other stuff to attract wider range of readers & older fans,
But the core audience are youngsters, that's why the formula doesn't change,
In case you haven't noticed, go check the reaction of SHs when Luffy declared his Secret Dream, those almost 20 or older either found it weirdly shocking or hilarious & crazy, but Chopper who is 17 years old clearly loved it so much instantly, that scene alone summarizes everything about the goal of this Manga, it's simply the fantasy of a 16-17 year old Oda (Which happens to be when He started his job),
The Formula will never change.