For a lot of people it's easier to learn English than Chinese - you wouldn't get far if you don't speak the language in China. English gets you very far in Europe though, most research institutions, universities, high end professions, etc already have English as the going language because of the international character of these places.

Chinese are far more open to working in foreign environments/contexts that Americans are, IMO. Just look at the foreign language learning statistics: most Americans tend to only know English, unless their family was fairly recently from a non-English speaking country. Meanwhile the Chinese landing in the US tend to already have decent English education, and dive right into doing what they're there to do.