They point is./..Apple only makes the phone. They don't have anything to do with the wireless plan. They sell the phone for $499 because they can. If and when they can't sell it for that much, they'll sell it for less.
Apple obviously had a lot of input about the monthly rates. They are lower than other plans and quite reasonable in comparison to other carriers, even to AT&T's own plans. So, I think you've over simplified your case.
I don't have a problem with Apple's price, what I have a problem with is the two year AT&T charges of at least $1440. That's simply outrageous for MY needs. Apple wants to sell the iPhone, I'm sure they're getting a small cut from AT&T but Apple's profits are coming from the phone itself, not from the service.
I'm sure they'll offer a PAYG plan in the future, it would be stupid for Apple not to.