Typical business attitude thinking cheap illegal labor will go on forever, even if they are legalized. Far from it.
If they are legalized, more illegal labor will come in to take their place. Real wages have been declining for over 40 years. If we had a shortage of labor, wages would be going up, not down.
I don't think that's the assumption.
There assumption is that we need an endless flow of new immigrant workers who may or may not start out being legal,
because as time goes on the ones who have been here for a while (and certainly their kids) will become Americanized and realize they can make just as much $$$ off taxpayers by faking disability and watching TV all day, than working a manual job in unpleasant conditions.