Yeah, but part of the reason is in Europe you can travel for 5 hours and find 5 different languages. My Polish MiL knew enough German and Russian to get her by. In the US, you can travel for days from one coast to the other and not need another language. And if you do need another language, odds are it is Spanish. And many people know some Spanish.
Combine this with the fact the Americans are generally the SOURCE of entertainment and culture like movies and music, that they don’t need to adapt to consume media from other countries.
So these two reasons are the biggest factors for why 15-20% of Americans are bilingual, vs 56% of Europeans (in the EU). In short, we don’t need it as much. We aren’t handicapped at all in our daily lives to live, work, and socialize with only one language. And other than Spanish, one would be hard pressed to find a use for any other language on a daily basis, unless you were dealing directly with say foreign media (like anime), a linguistics job (like translation or collaboration with people from another country), or an immigrant community (such as a church or charity organization).
I wouldn’t say that knowing 7 languages is “not uncommon” in Europe. Certainly more common than in the US, anyone who can speak 7 languages fairly fluently is an rarity - especially at 4.
