Bro how is Luffy not defeating the main boss of every island in front of everyone not a pattern other then Katakuri which was by design because Luffy was literally facing the mirror of his fruit
He didn't defeat Kuro nor Buggy in front of everyone,
he didn't defeat anyone in Loguetown or on Whiskey Peak (even less so in front of everyone),
he didn't defeat Mr. 3 in front of everyone (it was rather far away in the woods when they were alone after he had ran away),
he didn't defeat Enel in front of everyone (most Shandian were unconscious and the people of Angel Beach thought God was just answering their prayers),
He didn't defeat anyone on Water 7 and the Franky Family stuff stayed pretty much secret,
He didn't defeat any big bad on Sabaody or Impeldown or Marineford (in fact he lost),
He didn't defeat anyone on Zo and, as you said, he didn't defeat Katakuri in front of anyone.
But I do agree that he will end up defeating Kaido in front of everyone in the Flower Capital if that's what you mean.