What business model are you referring to? As far as I can tell they reduced prices mostly by (1) keeping wages as low as possible, and (2) by using their gatekeeper position to put their suppliers under pressure. I wouldn't call this an innovation. Also they improved their logistics, but I wouldn't consider this part of a business model.
Low-cost supplier is absolutely a classic business model.
If you want another one in retail compare and contrast with Costco. Which limits its number of SKUs (and actually has a reputation for paying workers relatively well by retail standards).
