They go down the rabbit hole of America's broken immigration system, starting with OPT visa, then H1B (read lottery luck, not based on skills) & then the country based quota for green card currently 7 to 9 years for EB2 categories for India & China. Did I forgot to mention the exorbitant out of state tuition fees and the loans they took for it in their home country ?
I had a lot of close Chinese(PRC) friends in college, and most of them were extremely rich. I know it's anecdotal, but I find it hard to believe a lot of Chinese exchange students are going deep into debt to afford US schools. From what they describe, the student visa interview process favors financially sound students.
That being said, what you've said about the visa system rings painfully true.
Lets think outside of America for this one. Lenders outside America are not idiots. Most of them lend on a solid collateral and someone from the family will have to have co-sign the loan, especially if its a huge sum.