If you really believe H1B holders are paid at least the prevailing rates and are hired only because of genuine shortages, then I got beach-front property in Arizona for sale.

Common sense says if someone cannot freely move between jobs, who faces immanent deportation if fired, who will have much better prospects of living well in US than their home country, then this person has much less leverage and would be paid less. It is easy to test this hypothesis: do H1B holders have a much higher rate of changing jobs after obtaining visa than their peers.