You're mostly right with your reasoning, but I don't think that will stop it from happening.
The original discussions between Apple and Verizon broke down because Verizon wasn't willing to give "ownership" of the customer to Apple. Verizon leverages (or used to leverage) its channel to nickel and dime its subscribers (e.g. disable bluetooth file browsing so they can charge you 25 cents to export a photo via an email to yourself or extort a monthly PictureMail package from you). Apple wanted none of that; they wanted a different uncluttered experience for iPhone users, and AT&T was more than willing to let them have it in exchange for exclusivity.
With Android, Verizon has started to loosen its grip on the subscriber a bit: a non-Verizon app store (The Marketplace) was a huge step for them. Remember, a few years ago, Verizon phones were much more limited. In fact, as a policy, Verizon refused WiFi capability for any phone on their network. I remember having discussions with their enterprise sales teams where they'd say things like, "Why would you ever want to waste your time and money building out a WiFi network when we've built the most reliable 3G network with coverage everywhere?" Umm... simultaneous voice and data, best path call routing with fixed-mobile convergence, coverage sucks in some buildings, etc. They've since realized that WiFi is a great way to offload some data traffic and maintain a more constant QoS for their customers. Anyway, this, along with attitudes toward Bluetooth and VoIP have changed, largely due to the influence of Android and Google.
On a side note, Google has been slacking a bit as a partner for Verizon. Verizon has been pushing and pushing them to make certain changes to the platform to make it more "enterprise ready" (e.g. device-wide policy enforcement, encrypted storage, for a couple), and it's taking too darn long. So, MOT and VZW have started to take some of this into their own hands, because their enterprise customers are telling them "no droids until they are at least as secure as the iPhone, but ideally as secure as Blackberry". Perhaps bringing another Android competitor into the stable will spur Google into action.
Anyway, my point is that Verizon is much more "open" than it used to be, but don't mistake "open" for FOSS in this discussion -- Verizon doesn't give a crap about that. They are simply more willing now to allow customers and partners to do more with their network, because they've proven to themselves that their network quality is enough to maintain retention and grow sales. So whereas before Verizon wanted no part of the Apple/iTunes/iPhone experience for fear of dilution of their brand and services, now they've "grown up", you could say, and they are willing to just Be The Network for some of their customers. Because, in the end, customers are customers.
Now after I've said all that, all my contacts at Apple and AT&T remind me that it was a 5 year deal for exclusivity, and that takes us into 2012. However, what they don't know is whether the iPad 3G deal modified that original agreement or not.