Phone Homes- The proliferation of cell phone stores

OK, can someone explain to me why there are so many damn phone stores out there? I can't believe how many stores are out there nowadays. I can't believe the major companies like AT&T, T-Mobile, and Sprint can afford to have so many stores in prime locations. In downtown Royal Oak, where the rents are such that the only stores that can survive have a high traffic rate (ie: restaurants), there's a T-Mobile store. How the hell can T-Mobile afford to have a Royal Oak storefront? Even at the mall, the T-Mobile kiosk moved into a store. And that's not even counting the party-store-come-wireless-expert stores that have popped up like mushrooms after a damp morning dew. I don't understand how these can even be profitable, since most of the money is made in the continuing contracts, not the initial retail sale of the phone. Are there that many phone sales? Are there that many people who have damaged / flushed their phones per day to keep the burn rate low in these stores? Can someone explain this to me, because I can't explain it.