Where there's a will, there's a way. For instance, citrus growers use tree shakers when slave labor isn't available. Grapes can be grown on special trellises that allow automation. I'm sure big cotton never thought there would be automation either (not that I'm comparing you to Big Cotton).
While there are probably some, I am constantly, but shouldn't be, amazed at the ingenuity of the human mind.
I lived in Stockton, Calif, in the late '60s when farm labor went out on strike at the height of the season. In one area, the desperate farmers were welding blades to their tractors to cut/harvest asparagus. Problem was, the blades cut immature as well as ripe stalks. Enter the geniuses at UC Davis. In THREE WEEKS they came up with a cutting device that used feelers to cut only plants at a certain height.
In the '70s I met an inventor who had over a dozen patents in food processing (he invented the machine to de-segment those canned Mandarin orange slices). He showed me a machine he had just patented that would DE-STEM strawberries without injuring them. Couldn't sell the machine to anybody as Mexican labor was cheaper (they'd tell the mothers if they wanted a job, they had to bring in their children and relatives to work for free).
Cheap labor stifles innovation. Unleash that American genius for innovation and a lot of this "labor shortage" will evaporate.