If some of you bothered to properly read what Oda said, he stated that Luffy was too weak back then and just a strong punch wouldn't be enough, he never said Luffy wouldn't win with a punch.
We got three major power-ups for Luffy and Kaido fighting multiple people to arrive at this point, and some of you still expect Luffy to deviate from his main fighting style simply because you couldn't read English properly?