>What happens when these people start to go home?

The US can very well be home for someone born elsewhere. It would be wrong to assume that those people are somehow just temporarily staying.

I’d imagine the group of foreign-born people who are in the US on time-limited or otherwise precarious visas is a lot smaller.

H1Bs would like to have a word with you… Even look at the number of people who are screwed in this job climate because of OPT limits.

American schools simply aren’t that good in many cases, because educators are more focused on political concerns that don’t matter

I think the numbers above actually make sense if you look at the pressures that influence decisions on what to study and whether to get a PhD for national vs international students.

If you're international getting a bachelors you need to find a company willing to sponsor when you graduate so it makes a lot more sense to pursue a STEM degree that is in high demand to employers.

For graduate students their is compounding pressure because getting a PhD allows the student to stay in the USA while they obtain the degree and STEM degrees qualify for the STEM OPT extension so instead of only having 1 year of work authorization post graduation you have 3 years. If the goal is to stay in the USA permanently it really doesn't make any sense to pursue a non STEM grad degree.

I don't have any commentary on whether the way the system is set up makes sense but I don't think it's just a case of American kids don't want to study these subjects rather theirs intense immigration pressure on international students to funnel them into STEM subjects.

Foreigners go into graduate study for the green card, not because of some massive fascination with the field. Local kids have no need for academia where you are paid poverty wages unless they are truly interested (professional degrees and and MBAs being the exception) or are looking to obtain a tenureship.

They're not high paying enough to offset how unpleasant it is for most people to work in these jobs. Double the salary and you'd see kids flock to these jobs. Continue to make these jobs available to people who are citizens of lower cost of living countries and the salaries remain depressed and really attractive only to that market.