[oscaracso]

I do not see how the facts you present call into question the basic logic that as you increase the availability of a commodity, say labour, you anticipate its price to diminish. All of the immigrant workers could be better-compensated and more productive than all of the American workers, and still their presence could drive the price of labour for native workers in that sector down. E.g., if there is a shortage of repairmen certified to fix some medical equipment, introducing a glut of new repairmen who are even more productive will fail to reduce the compensation of the incumbents only in exceptional circumstances.