For sure, this is the elephant in the room. It has gone out of control and now the illegal immigrants are an integral part of the economy: can't do it with them, can't do it without them.
Illegal immigrants coming to the USA know there is work for them. And life is better being an undocumented worker in the US than wherever they came from.
A month ago, I put an article about nefarious uses of "the corporation".
https://medium.com/@davevolek/nefarious-uses-of-corporations-0b1dad033621
Late in this long article, I explain how these employers can break the law and stay within the law at the same time--in terms of hiring illegal immigrants.