Keep in mind that the "WalMart effect" has happened in the farming community as well. Just as WalMart ran small shops out of business, large "corporate" farms ran the small farms out of business. There are a few small farms still around, but the farmers have regular jobs too. Small farms just can't make enough to support themselves anymore.
My step-dad works for one of these large farmers who farms 1,000s of acres of farmland. One year there was a flood so they got money from the government for the crop damage. Got over $1,000,000 for crops that were eaten by the local deer herd.