I don't think you're thinking of the historical details to say that in such a blase manner. The path to integration went through periods much more violent and contentious than anything we see today.
America’s secret superpower is the ability to assimilate pretty much any people within four generations give or take
The Muslims will (continue to) integrate as well. It takes a couple of generations.
Japanese Americans? Chinese Americans? Indian Americans?
Plus, the very concept of some sort of empirical “cultural incompatibility” seems highly questionable. I mean, it’s not like cultures change over time or anything like that.