Actually, the Walmart in my area has sold out some games on the first day. For example, when Call of Duty: Black Ops came out, they sold out by 11 a.m.
Well, I'm not surprised. They're not perfect. But it is sorta a half-ass secret most gamers don't realize. Places like Wal-Mart get the games on the same midnight release, too. Most people go to "game" places, and forget about the mainstream stores.
I count on preorders always, plus preorder bonuses, plus I have to have my CE. So yeah, I don't go there, but it's good for others. Mostly.