This is a One Piece trademark though. Luffy is able to move ahead in the world because he always improves on his ability while his opponents remain "stuck" in place because they got comfy and relied on one ability. Crocodile relied so much on the Logia's natural advantage that he had no counter once someone surpassed his ability, Hody Jones would pop roids like crazy because all he believed in was raw strength, Bellamy got armament haki but still relied on a move (Spring Hopper) that didn't touch Luffy two years ago. Luffy (and Nami) in the end beat Cracker because dude got too comfy relying on his biscuit soldiers that his stamina couldn't hold out. Dogtooth is about to get clapped up because he relied on his superior Observation haki too much and didn't hone/maintain his other skills as well.
I agree to an extent. It's a combination of that, and the fact that so many of Luffy's opponents underestimated him which led to their downfall. The difference between them and Katakuri is that he won't underestimate Luffy. He's shown superiority in not just COO, but also COA, and he has better mastery over his devil fruit. Honestly don't see any reasonable explanation for Luffy winning this fight unless it's an ass-pull. He sort of implied this chapter that gear 5th isn't going to happen, and awakening occuring mid-fight would also be bullshyt.