this is what will actually make it take off I believe. While a subset of Android devices support it, the marketing push it will receive when Apple bring it to their devices is what will drive adoption. All the news articles and other coverage that come when a new iPhone is announced will talk about how the new iphone is making the wallet obsolete etc, and people will get their first introduction to the technology.
I was disappointed the 4S didn't support it, as it would have been a good feature that only the 4S would have.
I believe the only reason that Apple (and the 4S) doesn't have NFC is that all the negotiations haven't been worked out yet. The technology is there and Apple has the know-how to make it a great user experience, but neither Apple nor Google live in a bubble. They need carrier support for NFC to work. Otherwise, they won't let NFC phones on their network. And don't forget Visa, Mastercard, et al. They want in on the action too.
I was disappointed the 4S didn't support it, as it would have been a good feature that only the 4S would have.