I wish they'd put one up near me. There's not a Wal-Mart anywhere in or even close to the 240 loop. It's a pain in the butt driving all the way out to the burbs to get cheap groceries. Most of the time, I'm too lazy and pay extra for the convenience of Kroger. Wal-Mart seems to have a phobia about cities. And it's not just about the logistics of density because that's not much of problem in my hometown. There are two Targets near me, both generic single story big boxes with acres of parking. And it's not about avoiding bad areas, because they have stores in neighborhoods that I would avoid.
Wal*Mart doesn't like urban settings. Rural and suburban? Of course. Big cities have high wages and high real estate costs, so don't expect Wal*Mart to locate itself in Midtown Manhattan where free-spenders appear. It has found itself capable of meeting favored demographics (blue-collar, non-union workers) who see only prices and distrust places with the word "dollar" in them. It can't compete with Cartier, Tiffany, or Neiman-Marcus because its information technology works for a mass market but not for economic elites whose choices are more capricious. It dislikes the low end of retail that attracts shoplifters and hot-check writers. I'm not saying that all urban dwellers are thieves, but enough are that they cut into profits and increase costs.
Wal*Mart has expanded into every niche that can fit it.