You got me there, but I still assert that the vast majority of immigrants aren't founders hiring Americans, and what's happening in Silicon Valley simply doesn't hold true many other places here in the US. In my part of the country, I'm actually much more frustrated with undocumented illegal immigrant labor than I am with student- or work-visa immigrant labor.

That's looking at it the wrong way. Look at the percentage of immigrants who are creating jobs, not the percentage of job-creaters who are immigrants. Or net jobs created by immigrants. Or something.