Now that you seem to have all the answers, please answer the most important question that you ignored-what about Target, Kmart and Costco? They fit the same mold and yet you have nothing to say about them. Why? Please use your freedom to explain to me why they are different?
Not exactly the same model, though Home Depot might. The difference is how Wal-Mart treats its suppliers and competators. For example, see:
http://www.fastcompany.com/magazine/77/walmart.html
(The bit you need to consider is the impact that this strategy ultimately has on quality. A supplier can't keep making the same goods for less, especially when their own raw material costs go up. They've got to cut something. At first, it may be waste but, ultimately, they'll start to cut quality -- and I think that's already happening.)
If you've got evidence of Target, K-Mart, or Costco doing the same thing, I'd be more than happy to look at it.