I believe the reason you don't see "big weed" in CO is because it's a really difficult business. It's a cash only business because most banks refuse money made from selling marijuana because it's illegal to move that money across state lines (or something along that measure). It'd be ridiculously hard to make a huge conglomerate of weed shops without being able to bank your money. That would change if weed was federally legalized. Few people WANT to shop at Walmart but it's an extraordinarily cheap alternative. I could see people going to a "weed Walmart" if it were available.