You can JB a iPhone and change the carrier name. For example, I could JB my iPhone and instead of listing the carrier as ATT, I could list it as Akugami, or my real name, or something vulgar and snarky like STFU. I'd take such visual evidence with a grain of salt unless you can confirm for us that it is indeed on Verizon by taking the phone and dialing *611 on it for customer service.
I'm not saying that Android isn't beating the iPhone in sales at the moment but there's nothing to suggest that the iPhone can't take a sizable chunk of the market. Look at RIM and their Blackberry. No one is signalling the same doom and gloom with them even though they are a single carrier with an OS that isn't licensed to anyone else. Granted they have more models of their phones and their phones are available on pretty much every carrier. The thing is that the iPhone will go to other carriers. It's a matter of sooner or later rather than if. You'd be crazy to think the iPhone won't get a boost in sales when that happens.