At the same time, the US getting educated and skilled workers that it never had to pay a dime for to educate. If you look at European countries, a lot of them are trying hard to prevent their skilled workers from leaving for the US.

If anything, these people are coming, paying high taxes whilst receiving only a tiny fraction of the benefits (no medicare, no unemployment, no education cost) etc. They may or may not be driving salaries down (pretty sure if the law was enforced it wouldn't be the case), but you can't ignore the rest.

There's also a lot of statistics on immigrants and children of immigrants founding a disproportionate amount of companies compared to US natives.