I went to a school that was heavy on immigrants and had lots of 1st gen citizens as students and all they did was advocate against people like me for admissions and for preferential admissions for their own group. So in my opinion, skilled immigration is not a transfer of talent but an expansion of the upper classes who go to war with each other over a small number of seats. Ironically this zero sum game keeps overall skill levels the same. For every immigrant, say, one citizen loses a seat somewhere.