As I'm sure Corby could tell, his article about Walmart upset me. I grew up in southern Missouri, just a few stone's throws north of the Walmart epicenter. While I don't think Walmart can be blamed per se for the current state of the food economy, the idea that they would be given such prominent credit for theoretically bringing positive impacts to small farmers smacks more of local-washing then it does of critical thinking.
Culture and economy cannot be separated. Together they form an ocean with many currents, and Walmart is one of the biggest tankers on that ocean. The wake it leaves can raise boats in some harbors and drown the whole town in another.
When I was growing up, pretty much everyone I knew had a large garden. I don't think most folks kept their own gardens because they enjoyed hoeing, weeding, and shoveling shit. They did it because it was one way they knew they could keep a certain amount of food on the table year-round. Every house that had a garden usually had a cupboard full of canned green beans, corn relish, and blackberry preserves, all delicious, but a heck of a lot of work to make. These habits were born more of necessity than pleasure.
As the generations change, fewer and fewer folks maintain these habits. Sure, a homegrown tomato beats anything at the store, but you're also likely to lose a lot of your effort to pests and rot. Why should anyone dig his own potatoes under a hot Ozark sun when he can run to Walmart and pick some up for a few pennies per pound?