These jobs used to pay a man enough to support a family. Where has the money gone? What happens if an illegal gets hurt? Do they get workmen's compensation? I'm sure they get a small settlement, the cut fixed, and sent home. All the people are complicit. It is all about growth and more profit. You can have a sustainable business and employees that get decent pay with benefits.
$20/hour is enough to do exactly that in most places that don't start with "San" and end with "Francisco". I know full well that not every illegal-immigrant-hiring industry pays that well, but it's my understanding that agriculture does, and that's one industry that seems to be disproportionately affected by the lack of undocumented workers.
> What happens if an illegal gets hurt? Do they get workmen's compensation?
In California at least, as far as workmen's compensation is concerned, illegal immigrants qualify as "employees"[1], so if a legal immigrant (or natural citizen) is entitled to it, then so is an illegal immigrant.
Of course, this varies from state to state.
Taxpayers might be harmed, but I suspect they'd be harmed much more severely by food prices skyrocketing because farms don't have sufficient labor to keep up with the demand from a growing national population (let alone global; California is the leading - and in some cases the only significant - exporter of a staggeringly-large number of fruits and vegetables).
Meanwhile, cracking down on illegal immigrants' ability to work and live in the US gives employers of said immigrants more leverage ("work these long hours for chump change or we'll report you and your whole family to the authorities"). Amnesty programs and other means to convert illegal immigrants into legal immigrants shifts at least some leverage back to the illegal worker, which then allows better negotiating power for higher wages and thus addresses the supposed problem that illegal workers are undercutting legal workers.