I have been an AT&T customer since the early 90's--almost 20 years.
But I bet because of the network issues, the flubbed launches, tethering, MMS, and now this, in 2011 I will be using my iPhone 4G on the Verizon network.
There is no way that Apple privately is happy with AT&T. No way.
Ill take that bet. Verizon WONT be carrying iPhones that soon, not when they are salivating for new crackberrys and hoping to get the Pre. They have shunned the iPhone once, and don't want to seem weak nor do they want to give their users any power over their phones without turning them upside down and shake all the money out of them. Examples: Crippled bluetooth, no wireless sync, Syncing only with phones that have funky cables you purchase from guess who, calling them to activate your phone when switching phones (that is so early 90's), etc. I'm not saying that Verizon will NEVER have iPhones on their network, they just won't have them anytime soon (2-3 years).
I too have been an AT&T, Cingular and The New AT&T customer for about the same time as you. Way before GSM, when Ericsson made decent phones. From TDMA to GSM I stuck with them, when they were bought out by Cingular, I stayed with them, and when Southwest Bell bought Cingular and changed the name back to AT&T I stayed. Well, they still suck. They are getting a bit better year after year. Their coverage isn't as good as Verizon (which uses old tech still), and sucks less than Sprint (why they still have crappy signals I have no idea).
The amazing thing is that the iPhone is such a nice piece of tech that even former Verizon customers will take AT&T's crappy network over theirs just to use it. You don't see that with RIMM or Palm stuff.