They will work for whatever is being paid when the going gets tough.
Well, when the going is really tough they will want to get those jobs. However compare the following candidates:
Obviously the immigrant is a better hire. He won't be bored at the job because it's on his gamma level. He won't ask for his rights because he isn't aware of any. And he is young and strong.
Fact is, engineers and scientists make poor farm workers. They aren't used to hard labor; many of them are old. They'd need to work for *less* money than an immigrant to get the job. This is not very likely.
In any case, it is wasteful to have millions of top notch specialists and send them to work the fields. That is reminiscent of policies of Mao and Pol Pot. Those "geniuses" had no use of educated people. Do we need to follow in their footsteps, to fail just like they did? You can't rebuild the wealth of the USA if all your industry is farms. The government should work on bringing high tech industry back into the USA.