Why is Apple signing exclusivity deals at all in the US? Down here (Australia) they just go with everyone. The do make them bend and turn and invent new plans that include a calls/texts/data package that's more to Apple's liking, but they go through everyone.
I suspect they had to, initially, and the only terms they could get were for several years (basically until now).
Every US phone is aligned with a carrier. It's not immediately clear to me why that is, but there you go. When the contract is up, Apple has a serious opportunity to shake that notion, but I'm not sure if they will.
AT&T is leaning heavily on Apple because it's scared, rightly so, that they'll lose a lot of money when the iPhone goes to Verizon, which it will.
I also don't approve of that snide little comment at the end. If you've got something to say, say it, and leave the snark somewhere that isn't here.