It's not beneath them per se. It's just that this trade only makes sense for a certain slice of the population at a certain time in their life. The immigrant is willing to work in that job because what is offered is not just the salary but something more (chance to immigrate, stability, arbitrage, etc.). It's similar to research assistants or grad students in universities. They are doing cutting edge research for peanuts because what they are getting is something more (degree, skills, future earning potential). It's hard to replace this dynamic. Or in other words, the dollar value of the intangibles is so high that if you were to put a price on it, it would make your business unviable.

> research assistants or grad students in universities

These are not fully trained scientists, but rather trainees. As such, they don't get paid the same as a fully trained scientist. Like how a journeyman is paid more than an apprentice electrician.

Of course, they are also underpaid, too. Ask any grad student union.

> It's hard to replace this dynamic. Or in other words, the dollar value of the intangibles is so high that if you were to put a price on it, it would make your business unviable.

Yes, it's very hard to pay your workers a liveable wage if everyone else is exploiting their workers by underpaying them.

All you're saying is that we've built exploiting labor (foreigners, interns, trainees) into our economy.