How many American teachers or firefighters would trade their own kid's job away to a foreigner in exchange for some hypothetical marginal increase in 401K returns? Not many. The only Americans who like that deal are managers who care more about their headcount than they do about their countrymen.

you keep thinking about it in Soviet zero sum terms. First of all, the foreign engineer doesn't disappear if you don't give him a visa, he or she just works somewhere else and still takes your kid's job away. Secondly, it's not a zero sum game ! that's the most important thing to realize. Number of jobs is not fixed ! it's not a fixed pie! you are on hacker news. A startup forum. And you are talking about number of jobs as a fixed pie.