It seems that according to you and a small amount of other people when the name changed to AT&T it suddenly went from top to bottom? They're coverage isn't spotty, at least not where I am in the East Coast.
Actually, they have been the worst US carrier for the past decade...period. Terrible signal, terrible pricing, terrible customer service, etc etc. They took forever to become competitive and were one of the main reasons people lobbied for the ability to move their phone numbers between carriers. They acted like they had a monopoly, so we all left. Then, without customers, shock of shock, they went out of business. Until Cingular bought them and the name change.
The consumer voted AT&T wireless DEAD. This is why they paid whatever it took to have something signature for the newly restored AT&T, ergo the iPhone.
And it's why the iPhone's sales with so far below expectation at release.
Hatred of AT&T >> Interest in iPhone.
And even the massive price cut won't help as much as Jobs needs/hopes. The iPod became ubiquitous because it was available EVERYWHERE. The iPhone will lose the chance to gain that level of success, unless unbundled officially from AT&T soon. Because Nokia, etc. are all working on iPhone clones. And they will all be out, affordable, and available from whoever you want to buy one from/for long before the AT&T exclusive deal expires.