This makes little sense. Illegal immigrants usually occupy the least qualified and least-paid jobs. Few persons that are qualified to apply for a manufacturing would rather apply for a job that an illegal immigrant could get.
Do the illegal immigrants take those jobs because they pay so little, or do those jobs pay so little because there has always been a steady supply of illegal immigrants desperate to fill them at below-market prices?
If your business model relies on wages being suppressed by those illegal workers, then maybe your business deserves to go bankrupt when the supply dries up and Americans start demanding $15/hour.
First off, these businesses typically don’t “rely on” those wages, the owner is just taking a $20k bonus because they can and they like money.
Undocumented workers take the jobs because there is no financial incentive for an owner to risk breaking the law unless they are getting cash back. The worker is basically paying their employer to break the law.