California just endured a shutdown of several grocery store chains. Since Wal-Mart is busting everyone's chops to keep costs down ,and since they're become one of the biggest grocery stores in the country in just a few short years, the national and regional chains see what was done to "mom and pop" hardware stores, clothing stores, five and dime stores, pharmacies, etc., and are scared shitless. They have to compete somehow or perish, and their biggest cost is salaries.
Personally I think Wal-Mart's produce is shit, but the wife goes there because, generally, the prices are lower than at the major food stores (Kroger, Randall's and H-E-B). I refuse to go there for anything unless I have absolutely NO CHOICE. Fortunately, I usually do have alternatives.
(And don't even get me started on the arrogant, pathethic, pompous, overbearing, know-it-all Wal-Mart employees and shills who troll the Internet boards...)