"这么多留学生" are only about 5% of total college students.

About 20% foreign students come from China, 1% of total college students.

It's hard to find work in US now, majority have to leave US. For the annual 75000 H1B visa, more than half offer to people didn't study in US and just come to work. And many of those 75000 H1B don't get greencard.

So at most 30000 students per year could immigrate to US, compare with 300000000 population, and 1000000 total immigration per year.

You don't have to worry about them.