I've seen a couple of (very limited) examples of restaurants using their contracts with suppliers to open small local grocery stores near their restaurants, that undercut the big grocery chains. If anything was possible, I'd prefer more local neighbourhood stores for packaged foods and community garden co-ops combined with farmer's markets for fresh foods.

I dont know, more competitors would still be better.

Ive see my low no frills lower prices to match Walmart sales.

There aren't that many Wallmarts relative to grocery stores and they also aren't usually in the same areas that people do grocery shopping, so I don't think they are a significant competition.