iPhone carrier exclusivity: Coming to an end?

It's one of the big questions everyone wants answered about the iPhone: when will carrier exclusivity end, ridding us of the ball-and-chain that is AT&T?

I'm starting to believe the recent rumors of a CDMA iPhone being released on Verizon before the end of the year. Here's my reasoning

• AT&T recently upped the early termination fee for canceling a contract from $175 to $375. That's a pretty big jump, and would definitely provide incentive for people to keep their new contract.
• Early upgrades for most users - AT&T made the iPhone 4 upgrade eligible early...up to six months in some cases.

Why does this point to the end of exclusivity?

Apple is giving AT&T one last bonanza of iPhone users through the iPhone 4 launch. When the dust settles, and the majority of users are signed up for their new cellular contracts, Apple will launch the iPhone on Verizon. AT&T will be in a decent position with their existing customers, who will need to pay a premium to defect.

This would undoubtably piss quite a few people off, but do you think AT&T really cares that much, considering their recent service track record? My guess is they're banking on a lot subscribers leaving for another carrier eventually anyway (once they can take their iPhone with them) and are looking to cash in now.