The lack of an iPhone at Verizon might have been "contractual obligations with AT&T" over the last few years. But overall, it was Apple wanting special treatment. Does Verizon really need that?
I'm sure they could have had the iPhone if they wanted it, but from the cell provider perspective, it's dangerous to give over so much to a hardware vendor just to get their item.
And for the vendor, Android is the opposite of this. You can pay a little for "Google Experience", or do it all free and add your own home shell (HTC Touch, Moto Blur)... just what the vendors wanted. This is also a critical long-term thing, since the platform, Android or iPhone or whatever, will have to get lower-end still to emerge as the dominant smart phone platform. Android is already there: free OS, lower rez screen support, etc.
Some prespective: a billion cell phones are sold world wide.. each year. Apple, after three+ years, has a reported 54 million "iPhone OS" devices, 40% of which are iPods Touch. This indicates that, if you move a little cheaper, you could dust Apple's installed base in a few months, much less a few years. I think Android should go there, too, not just to the "iPod Killer" market.
Plus, there's the whole marketing aspect. Verizon has been spending millions per month to promote DROID/DROID Eris and diss the iPhone. They have been pretty successful at this, but it also looks like a bridge burned. I don't think they need it, but at this point, I'll wager they're on poor terms with Apple, and as well, they have put the iPhone on "the island of misfit toys" ... even in selling their network over the device, they would have some public crow to eat, and perhaps extra money to Apple, if they suddenly decided to back the iPhone.
I think their efforts are better spend getting next year's 4G rollout done, and supplying some Android devices to service that. I do strong believe they have backed the better horse here, on many, many levels (open system, open software, Apple's ego, etc).