He does that sometimes but not all the time same for other manga authors but then again that is something happen in a lot of fiction no matter the media.
Chapter 1000 is literally titled Straw Hat Luffy and is Luffy entering a fight involving two Yonkou.
The amount of planning that takes is insane. That's why we had the Ice Oni and all that filler: so Luffy would wind up on the roof, on Chapter 1000. Oda's skill as an artist isn't the question, it's his decision making.
He should do what he wants, but I'll pipe up when his plot decisions break my mind.
It's a trade off, because chapters like 1000 hit hard as hell. Just wish we could get there without so much baiting, filler, and silhouettes.