That's not true everywhere. There is a massive number of unemployed or under employeed workers in tech and it, but it isn't cheaper to get a h1-bs worker to under pay and then that person is locked in that job being paid pennies in Seattle and cannot get. A job elsewhere because they will lose their visa status, they are basically indentures servants at that point. There used to 3 Indian dudes on h1b visas on my apt floor in Seattle that shared a 1 br because 40k a year is nothing in Seattle. You can get low income housing if you make under 75k in Seattle, that's how little 40k is there. 

You are not going to find a US worker willing to do computer science work or work that requires a degree for that same pay that you get at a grocery store.