I have never been a fan of Walmart and try to avoid it as much as possible. My mother is proud to say that she has never entered one. It is just too big, an overwhelming super power. It always buys in bulk and sells as cheap as possible and blah blah blah, BUT things may be looking up in the sustainable consumption department. Check it out:
http://www.theatlantic.com/magazine/archive/2010/03/the-great-grocery-smackdown/7904/
They have so much power that it might actually work! Maybe one day my mom won't go anywhere except for Walmart....maybe not, but the point is that maybe mainstream will work after all.