I don't think leo understood my point, so allow me to reiterate. I'm not saying One Piece doesn't deserve it's success. I'm saying because of it's success, Oda is given complete control over what he's allowed to write, and for how long he's allowed to write it. No one is pressuring Oda to hurry AT ALL. If he wanted to write 100 chapters on a side character on an island completely unrelated to the current plot HE COULD and no one would say anything to him.
Other mangaka are not allowed that sort of artistic freedom. Shima had to make sacrifices left and right in his story, like having to completely skip out on showing the acquisition on some of Acacia's Full Course dishes, all so he could fit the conclusion of the series in X amount of chapters. Jump gave him a deadline. No one gives Oda deadlines EVER.
So while it's true that One Piece has the best world building of any manga, just remember that Oda is allowed to fully flesh out his world to a degree that other mangaka would not be able to. It's the best because it's allowed to be the best.
You didn't understand my point and you are inverting the order of things. Let's try again. He is allowed to do what you said because he earned the respect of the editorial body, they know that his decisions are 99% right, he is a genius, it is not only because he sells 2 million.
And you are inverting things, One Piece is not the best because it is allowed to be the best, it was the best first, before allowing to be even better. Maybe it is because it was 20 years ago, but you know that Oda was a rookie and One Piece is still his first series, right? He started like any other mangaka in Jump, One Piece didn't started selling 2 million right of the bat. The series didn't become good after One Piece started to sell 2 million and Oda earned more freedom, it was good since the beginning and got popular because of that, so your last phrase is simply wrong. Oda felt the pressure for some time before Shueisha realizes that they were dealing with someone otherworldly special. Now he probably doesn't feel the pressure from the editorial department he is the greatest of all time and Shueisha wants it to run as much as possible, this is just normal and I think it was the same with very popular series like Dragon Ball, Slam Dunk and so forth. However, Oda feels the pressure coming from himself because he is not allowing his series to decrease in quality because he is who he is. Even if it was bad, the series would continue running because Shueisha would like to, but it is good and it is good because of Oda continuous search for perfection.
So, the only explanation for me that you think it is unfair the difference in treatment is that you think Shimabukuro is as good as Oda (something that even Shimabukuro doesn't think he is) and that Toriko would have had a success comparable with One Piece. This complain should be directed to Japanese readers, maybe, but I think the readers are not in the wrong here. Toriko was good, very good at the beginning, I liked it a lot, but it went through the same thing every series, except One Piece, go through, the quality decreased a lot and the readers are not that forgiving.