Do you have an details on the wage differences between immigrants vs U.S. workers? I was under the possibly mistaken impression that companies were not allowed to pay H1B workers less.
They aren't, but it's a largely unenforceable and really pretty stupid provision in a field with such a massive difference in productivity between workers.
Sure, I suppose you can require that a company pay some posted "prevailing wage", but that that hardly tells you this is the wage an individual would get if he or she were free to find another employer, join or found a startup, or enter a different field entirely.