I thought it worth mentioning that "Price Matching" is somewhat of a scam. The logic being that if every retailer will sell something for the same price as every other retailer, there is no incentive to lower prices. I'm surprised gas stations don't get together and do it, although it'd probably be illegal.
It is illegal. It's called collusion.
Price is not always the deciding factor when a purchase is made. People are willing to go to an Apple store and pay more, because of the service they get. Knowledgeable salespeople, genius bar, and so on. Others may go because of the atmosphere of the store.
Others may buy online or at a local retailer due to the distance between them and the closest Apple store. Others may not have reliable transportation, and buy online. Others may prefer doing their business at a trusted store where they have done business for years. Some may be intimidated by the Apple stores. I know I like to get in and get out, I'm not a touchy-feely-browsy type of person. I know what I want before I go.
Apple stores can eat the 10% because they are working on their own retail margins, not a big box store's. With the latter, you have to consider Apple's margin as well as the margin of the retailer.
I do think it is a bad idea to use Apple products as a "loss leader" unless you can upsell warranties, accessories, etc at the time of purchase to make up for the loss. Even with the premium Apple prices, I think it cheapens the brand image.