I left the US because I finally got fed up of the treatment of anyone foreign - I was working at a top US university on an international project, but every time I returned from a conference or field work I had to convince some not finished high school rent-a-cop at immigration that I was allowed back in. I wasn't allowed on field work in the US because the research plane flying the experiment and equipment I designed had the door to the cockpit open - and as a foreigner I couldn't get airport security clearance to be on such a flight.
The bioscience people left the US long ago for countries where 4000year old mythology didn't dictate what you could work on, the physical scientists are going now.
Still if you get rid of all the immigrants the US will be a world leader in beaded blankets and feather headresses.