NFC is a neat technology, but it isn't terribly useful without a rich ecosystem in which to use it. Payments come to mind, but a lot of people have tried this before. While prior efforts haven't been a total flop, they aren't exactly exploding with popularity.
Every year there are rumors of the iPhone gaining NFC. Every year the event passes without mention of NFC. Until now, maybe.
I'm not sold on the notion that the iPhone 6 will have NFC, but I wouldn't bet against it at this point like I would have confidently in years past. If Apple does add NFC it will be accompanied by a launch of a rich platform in an attempt to drive their solution to complete ubiquity - on iOS devices only, naturally.
They already have hundreds of millions of credit cards on file. They already have a secure payment infrastructure. Apple is uniquely positioned to offer services to their customers that are tremendously secure and protect your data. Apple makes money from devices and that requires people trust their devices. Other services, offered for free, are rarely incentivized to provide the same level of protection. Coupled with iBeacon you could make the argument that a "retail 2.0" experience could be possible should Apple be successful in their hypothetical effort. There are speed bumps though. This would require a lot of retailers getting a lot of new hardware - though inexpensive, it is still nontrivial.
If they launch a wallet solution like they launched Passbook*, I don't have much confidence we'll see it take off. I also don't see them doing something like that. With Bluetooth Low Energy, Apple has very little reason to add NFC unless they are going to hit a grand slam with it.
The wallet is a concept that is painfully ready to be redesigned from the ground up. There are privacy and security concerns to slow down progress, not to mention legal concerns given the need to carry a photo ID as an adult.
I think that Apple is uniquely positioned to do something about it, at least in the US. Their devices are "everywhere," they have a tremendous incentive to keep your data totally secure, people trust them, governments trust them more than most tech companies, and the more they can lock you into their walled garden the better (for them).
I think it is safe to say that September 9, 2014 will be a day to remember for many reasons. If nothing else, it just might finally be the day that the annual NFC predictions finally come to fruition.
*I love Passbook, but it hasn't exactly gone mainstream and adding passes is tremendously confusing for most people, especially when it launched with very little app support.