that doesn't change the economics at all.
the money paid to the worker through a middle-man has no bearing on the labor market as seen by the company and their bottom-line. You could send your paycheck into the incinerator every month... it makes no difference.
as you say the $80k is the rate to avoid hiring a US employee. maybe that's lower than what it would be with no h1-b, but then what are these displaced american workers doing for more than $80k?
as you say the $80k is the rate to avoid hiring a US employee. maybe that's lower than what it would be with no h1-b, but then what are these displaced american workers doing for more than $80k?