Well, there's that, and there's also the fact that it's historically been a good bet with the iPhone to order each new model sight-unseen. That's been the case going back to the very first one.
Not every new iPhone or iOS version was a win in every respect over its predecessor, but this is the first time Apple has royally hosed its customers.
Antennagate was mostly a made-up thing, though. It served certain peoples' interests to turn it into a bigger deal than it was.
Maps is a huge part of the reason why I bought an iPhone in the first place. I would literally rather give up the ability to use it as a telephone than give up the ability to use it for navigation.
Are there any books or dissertations written on this phenomenon?
Certainly psychiatrists have a name for this by now? (I have never seen this level of loyalty anywhere else: Rock Stars, World Leaders or Religious heads..)
Its almost like some drug is leaking into their bodies from their iDevices which rest of us are not privy to.
As much as we may make fun of "fanbois", it's incredible the amount of loyalty, trust, and goodwill Apple has managed to generate for themselves.