The Ag industry can exist without cheap foreign labor. Advanced robotic fruit and produce picking machines are now available and there is no real need for them. The cost of growing produce is a small pet of the retail supermarket price. This a no/brainier.
People need to go over to Youtube and look at what kind of mechanized farming is taking place. Boring videos but amazing technology. If you haven went to Youtube to see for yourself then you likely have no clue because it doesn't make the news or TV Drama shows.
Start here then look at how they build railroads and bridges or cut timber.