Perhaps one of the reasons it is cheaper to ire illegals, is that many of their needs are met by the taxpayers, instead of their employers. That would make a great headline in the Bee or even the Times (God forbid).
Bingo. The 'Real' cost of Illegals is hidden. The only real beneficiary as far as I can tell is the Employer who manages to shift substantial costs to others where they are very well hidden but nonetheless paid.