Also, the cost of produce at your stores is more about the cost of transportation. The current cheap gas prices are due to fracking, which in turn produces wells which taper off far faster than traditional drilling. That will end, and prices will go back up. And food costs will increase. Just like they did back when gas was twice its current cost. Even in the past few years, there have been specific shortages in commercial ag, such as eggs last summer, when many commercial chicken farms had problems with disease, which is another cost factor. Large-scale ag means large-scale transportation and logistics and THAT is where costs come from, not the labor cost of digging up dirt.

That is also why the micro-ag folks can undercut prices despite higher labor costs (if they even hire out labor at all) -- they sell locally, and their transport costs are minimal. Often as simple as throwing produce in your truck and just delivering it across town, or to a local market.

And on the labor question, the next 4 years may change costs if Trump really does cut down on illegal aliens. Wherever you stand politically, they are the source of cheap agricultural labor in the USA.

All of this does not mean that tech won't change things in the future - it very well might. But that same tech will be available to small-scale ag, so there is no reason to assume that production gains will only apply to commercial farming. The disruption that could change the picture is cheap, renewable energy propelling self-driving trucks.