But these prices are for "qualified customers only", meaning they are subsidized prices. You can get them if you are a new AT&T customer or if you are approaching the end of a contract (making you eligible for a new phone at subsidized prices. If you're not "qualified" and don't want to wait for your contract to expire before upgrading, then you have to pay full price (See the fine print at the bottom of this page) which is $400 higher. But in an unusual gesture, AT&T is offering "early upgrade" pricing of only $200 higher for customers who have less than a year left in an existing iPhone contract.
As far as I know, this is standard for the cell phone business. If you want to buy a new phone and you're nowhere near the end of your contract, then you have to pay full price, which is several hundred dollars higher than the subsidized price. That was the case with both of my phones from Verizon and is (as far as I know) the case for all phones from all carriers in the US.
But apparently, many iPhone users are completely clueless about this, or they just enjoy complaining. This afternoon, I ran across this article which was apparently written by someone who has never done business with a cell phone company before. He makes it sound like existing iPhone customers are being punished, because they have to pay more than new customers. (He doesn't make any mention of the fact that existing customers can get the same price if they wait for their contract to lapse.) And the people commenting on the article seem to be taking it as a personal attack by Apple Corporation itself.
To these people: get a life, get a brain, and learn to read contracts before signing them. You're not going to get something for nothing, no matter how loudly you scream "but I want it and I want it for free and I want it now". If you want to act like a 6-year-old child, then my only answer to you is "go to your room until you learn some manners."
If you want to complain about industry-standard pricing practices, fine, but this is hardly isolated to the iPhone. If you don't want a contractual obligation, then you aren't going to be able to get a subsidized price. But given the hatred Apple got in return for selling the first-generation iPhones without a subsidy (for $600), I doubt the whiners would like that either.