Depends on the place and where the H1-B is from. I have seen situations where H1-B works make half of the American worker. One tactic I have seen is that the American companies tend to basically lock in the workers by paying legal fees and dangle the green card sponsorship carat. The H1-B individuals typically will put up with this for the chance at perm residency. While not all of them, make no mistake there is a real new indentured servant class.