I have friends that have lived, worked and farmed in Watsonville, CA for a long time. My wife's grandfather has also farmed in MI for decades. The consensus is that farm-workers are getting harder and harder to come by. There is a labor shortage. This shortage has encouraged the investments and greater interest in picking technologies.

So to reframe, there are fewer farm workers anyway, due to better border control, lack of interest, or whatever and the picking technologies become more useful.