Somewhat, the other side of the coin is if they can even find labor at a price that has a chance of competing with growers who have local access to cheaper labor because they're in poorer countries. The price they'd have to pay to get legal pickers is more likely to fully drive those farms out of business or at least out of those crops into more machine harvestable crops.

The main point though is that the "problem" of seasonal farm workers staying in the US illegally is to some extent artificially created by attempting to strictly enforce the border. Before that they were able to come work freely and would happily return to their home country because the process of getting into the US for the harvesting seasons was (relative to the modern process) easy, safe and cheap so there was no reason to stay in the US. Why would they, their wages would go farther in their home countries and that's where their families were and they would be able to cross back for the next major harvest they wanted to participate in.

We're not talking about slaves here... and someone does need to pick the food from the vine, big ag has tried for decades to automate picking of various fruits to little success. It turns out recognizing and handling ripe fruit is a difficult task for both vision and effectors.

The point is that families didn't just evacuate when it turned into US territory. There are very strong ties to Mexico in the southwest that will never go away.