In grad school i was one of those TAs teaching science to 1st/2nd year university kids. Let me tell you, i was horrified and could not believe these kids paid $50k/year to attend these essentially "baby sitting" classes with high school level information.. at most. 95% kids knew nothing IMO and were planning to go to med schools, i pissed off many of them (as i later discovered) by not giving them anything higher than a C (honestly they deserved to fail). They thought i was too hard one them, but all i was looking for is understanding of the subject and they clearly had very over the surface level of understanding .. Where i come from they would not even be able to enter the university at all...

To me the educational system is clearly broken, most schools in USA are unable to produce quality talent. One of the things that annoyed me was the love of multiple choice tests .. i never encountered one in academia until i came to the USA. What, they tell you the answer when you take the test? Whats the point of the test?

Until USA fixes education system ground up starting from the elementary school to high school to college there will continue to be a need for talent from outside of the country. Until teaching becomes a highly respected and competitive profession (see Japan) - things will not change.

There is a lot of demand for smart well educated people in this country and Since America does not have enough of these people inside (see last election results lol) there will continue to be a flow of brains from the outside of the country.