> However, if you look closely, even that pipeline is kind of skewed. Very few Americans pursue advanced degrees, and even when they do, they concentrate towards business or some other non stem course.
I would imagine this is a symptom of immigration abuse more than a rationale for more of these visas, as if often touted.
Besides tech, US universities are probably the biggest abuser of the foreign worker / visa pipeline. Not only for workers themselves, but the educational system itself now caters to inflated tuition paying foreigners who know they'll be awarded, on top of their degree, an OPT or similar visa that will allow them to chain it to another longer term method like Perm residence, marriage, H1B, etc - such that they'll be here for decades with the ability to remain and work and (push down wages for citizens), even though the original deal was they were coming here to study for 2 years and then go back home.
If you were a smart 20 year old American deciding on your major, and you noticed that 90% of the tech classes were foreigners, what would you do? And furthermore, the graduate tech programs didn't even seem to want you, because they knew they could get a foreigner to pay 2x as much tuition and / or work twice as hard, because the gov't was allowing the college to essentially "sell" a work visa along with the diploma to the foreign students.
If I were advising some bright 20 year old, I'd tell them to run from academia and tech as fast as they can - use their smarts in law or medicine where you'll make 2x as much with 2x the respect, and you won't be competing against millions of foreign workers in your own country.