If Apple and AT&T want to control the whole phone (or VZW for that matter), then rent the phone like you used to that big ugly black house phone.
More importantly: take it back and recycle it when the contract is up. Right now, I buy a phone, usually subsidized, but at the end I'm left with a phone that isn't much use. It is locked to a specific carrier network. Recycling it is very challenging. (If it isn't let me know, I have 2 complete phone kits in my closet). And they are piling up in landfills. Carriers don't even have a trade-in program like car dealers do.