A lot of people in usa don’t even speak English. I constantly run into those even in the South, let alone big big cities which have posters/ads/instructions label/etc. in foreign languages in public places.
Guess how many people in europe don't even speak:
Bulgarian, Croatian, Czech, Danish, Dutch, English, Estonian, Finnish, French, German, Greek, Hungarian, Irish, Italian, Latvian, Lithuanian, Maltese, Polish, Portuguese, Romanian, Slovak, Slovenian, Spanish or Swedish... or even Esperanto!
FWIW, as an American living in Europe, I do agree that the US is far more homogenous.