What exactly people mean with the raid failing? That we are going to get like a time skip and them a week after the raid the SH & cia will try again to beat Kaido? Thats kind of nonsense.
I think its quite clear that Luffy will not win this rooftop round against Kaido, and that the there will be more rounds to his fight with Kaido, like with any enemy, but there's no more room for the raid to fail, with all this build up of this night being the night before the dawn for Wano.