Like Cubans after the revolution, or Iranians after their revolution, or maybe the mass of Vietnamese after the war? What actual cultures are you saying are incompatible? America has worked with them all and despite hand-wringing over "compatibility". There is a much stronger case to be made human beings are humans in the end and that it just takes time.

So, only white people can assimilate then? The now many generations of people of Hispanic origin that are part of the American story would seem to indicate you are wrong. As is the case with the now multiple generations of Koreans and particularly Japanese, who remain part of the US story even after being put into concentration camps because of precisely the same sort of prejudice, that they were somehow inherently un-American due to their "cultural incompatibility", i.e. non-whiteness, unlike the millions of German-Americans in the US at the time.

The Muslims will (continue to) integrate as well. It takes a couple of generations.

That’s not true. When German immigrants were new, no one believed they would integrate since they refused to give up speaking German. Catholics like the Irish were viewed with suspicion because they revered a pope.

America’s secret superpower is the ability to assimilate pretty much any people within four generations give or take

> I think the current situation in Europe, and other instances of mass migration in history, demonstrate that not all cultures are compatible with each other.

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.

"cultural compatibility"... Sounds like a concept created by someone who hasn't met people from very many cultures.