Its a misnomer that workers who pick our food never leave - they are not illegals but Green Card holders - as for importing food, perhaps you’d like to try the latest eggs from China - made from waste chemicals.
No its is not cheaper to import food in the short or long run. Our food is better quality and could once again be abundant, returning to a net exporter of food.
Go work in the fields if your are not too old. I once did. honest hard work, try it some time.