This misunderstands the purpose of ICE, I think.
They're helping intensify the abuse of migrant labor, not trying to reduce it. Their purpose is to terrify migrant workers into compliance and obedience and silence. The problem, of course, is that this can only be pushed so far - like squeezing blood from stone. Eventually, no amount of additional terror will result in labor intensification because it can't actually be intensified further.
The next step would be labor camps.