There are only 2 million unemployed Americans right now. Most of the illegal immigrants have jobs and fill in the gaps, such as working on farms and factories. If the 20 million illegal immigrants are deported, want that create a massive laborer shortage? Won’t the work follow the workers to Mexico?
That is nice economic theory.
The reality is only small entities will close and will be absorbed by the bigger companies that can afford to shift production to other countries and prices will go up because they can. The only reason why they produce locally is because of subsidies and illegal labor.
There is no economic incentive to pay a desirable wage domestically when you can exploit the workers of another country and make more money.
If it requires illegal labor now, it will be offshore if illegals(and “accidentally” the wrong color people) are deported.