So why are so many of them established here, working and sending money home to Mexico & Central America?
Not votes, people: jobs.
If employers were penalized for hiring them they'd stop coming here for work. OTOH, there's reality: I think it was the Governor of Texas who said that if every illegal working were sent home, there wouldn't be a restaurant left open in the whole state. [What they didn't say was that legislators would also lose their gardeners, nannies, and drivers, too.]
Illegals don't come here to vote - that's a nice deflection by those who benefit from the cheap labor, and since many of the beneficiaries are legislators, we, the people, lose again.