But other then that you're right, and lets not forget the huge brain drain into America over the years.
Attracted both by the economy but also by the level of freedom.
Not just democratic freedom, but also the freedom to not stand out just because you look different.
This is true - and the brain drains are probably what made America great. Before and during WW2 some of smartest people in Europe (mostly Jewish) fled to America and they never went back. That is probably one of the reasons why the USA was off much better after WW2 than other countries.
This continued over the years. But it can easily reverse - if situations in the home countries become more favourable or if the USA decreases the number of Visas...