Oda doesn't care about consistency or power in his story. Plot over all. I mean even just using kaido and Luffy where he knocked Luffy into the ocean the cursed himself saying she should have taken luffy's head otherwise the alliance wouldn't think he's dead. For kaido to ko Luffy again then just assume he's dead not take his head then fly down from the rooftop to only have happen what he already said would happen which is that those below wouldn't think he's dead. Oda doesn't care about his own inconsistencies as long as the plot is moving in the direction it's supposed to. That's really the only problem with op is that there's no consistent power. Like I'm sure despite Luffy now being 1 of the strongest characters ever he will still somehow get caught or restrained by characters vastly weaker than himself.