Employers just hire experienced h1bs instead, they won’t leave after being trained, no reason to hire an American
People are also now learning this fact, which is why you’re getting unpalatable politicians elected.
Irony is, that doesn't prevent such sentiments as yours leading to people like Trump. I had a chance to live in the USA years back, I'm glad I didn't bother to take it.
Do you have numbers? If you don’t, the appropriate baseline is population.