If you really want to solve the problem, there's just a few small things to fix in the American system.
First, you need to make your town centers and such into attractive, vital places where people like to go. Accessible to all, lots of parking (unobtrusively), good stuff for kids and families, etc. Make the parking free, too -- it is at the big WalMart, right?.
Second, you need to zone your town center such that big chainstores cannot open there. This requires very strict and complicated systems: no shops larger than X floorspace, special rules about chains, and on and on. Systems like this are always problematic, I should note.
Third, you need special rent-inducements and such to entice butchers, grocers (in the old sense), and so on to open small shops and give it a go.
Fourth, you need to do everything imaginable to keep the big stores from opening anywhere within a stone's throw of the town center -- make them open in the boonies somewhere.
If that sounds like a lot of money just on the off-chance that it might work, you're right. That's exactly why it never works: big conglomerates always have the advantages, because everything else is a bunch of non-experts trying to sort of get it together, and the big guns like WalMart can smash them easily.
What you have to achieve, of course, is a new kind of American shopper. You need, in vast quantity, the kind who gets 1-stop shopping via multiple small stores. This hasn't been done yet, that I know of, and I doubt it can be done. The primary difficulty being that it is every American's God-given right to drive a huge gas-guzzling car straight up to one single enormous store, fill the back with a lot of garbage, and drive it all home again. Asking that American to walk from store to store is, well, un-American.
The only way I can see revitalizing things is to create a new kind of store (such as exists in many parts of the world, but not, that I have yet stumbled upon, in the US): the mega-mom&pop. Basically you have a big mall sort of thing, but it's jam-packed with small stores. No chains allowed, apart from maybe one or two big ones that pay a whacking great surcharge to be the "anchors" or whatever. Everything else is a genuine mom&pop that happens to rent space from the mall rather than from some landlord who happens to own the land under the shop.
It could work, IF... you can get a critical mass of young-ish mothers who know each other from the local schools, sports, health clubs, spas, whatever, to go there. The idea is this: drop off the kids at school, go to the mom&popMall, have a coffee, chat with a pal, buy your meat, see a friend and have a coffee with her, buy your produce, see another friend and decide to meet up later for Spinning class, etc.
I know this sounds sexist, narrow-minded, whatever, but the fact is that every community I know has a significant group of people more or less like this, and most of them are women. If they start using a place like this for preference -- and it would help immensely if "mom" of the mom&pop butcher were personable, knowledgeable, and interested in knowing every little detail about her customers and willing to pass on the news -- that will be the kiss of death for WalMart et al., because you've got all the same conveniences with the newly added advantage of personability, service, and knowledge.
'Course, you're also going to have to convince all these people that when they buy meat, it doesn't have to be rushed immediately home and slammed in the fridge to avoid botulism and trichinosis and salmonella and AIDS all at the same time. Otherwise it's all moot: you can't get those customers to sit and chat with one another and take time at their shopping -- which is what this system would encourage -- if they think everything is going to rot while they do it.
Personally, I don't think it's going to happen. I'd say the American food system is doomed to chainstores until the distribution system dies almost completely and those who aren't very rich are genuinely forced to rely on what is more or less local.