I think I need to drop some knowledge:
1) iBeacons is one-way, from the beacon to the device. Already a non-starter.
2) Bluetooth LE requires pairing which in the over-polluted 2.4Ghz spectrum is a horrendous experience.
3) WiFi is even worse since it's not secure until you have a password, and how do you get that in the first place?
Bluetooth and WiFi have even worse problems because they actually work over a long range. The last thing you need is someone capturing traffic to decrypt later (hence the *near* part in NFC).
People need to stop confusing the technology (NFC) with the implementation (whatever Apple does with it - hooking in TouchID, credit cards, etc..). They aren't the same.
As far as my reasons for why Apple hasn't included NFC:
1) Chassis only changes once every 2 years. The current design is already packed, and you need a rather large (but thin) NFC antenna to work. And every rumor out there says iPhone 6 will be bigger than the 5S.
2) Integration of NFC into wireless chipset (Bluetooth, WiFi) wasn't available until last year.
Finally a sensible post about the differences between iBeacon / BTLE and WiFi and why they aren't NFC and not suitable for payments.
I'll add one more, as well as encrypted BTLE requiring pairing, it's not particularly secure. The 6 digit pairing pin which is what you most often see used gives very little security and even a sniffer based on small mobile chips can test those combinations in a fraction of a second and sniff the encrypted link as long as it listens to the entire conversation, it's literally a matter of trying them out. Classic Bluetooth doesn't have this issue by the way and one day the SIG is going to have to address this.
The one secure way of pairing is an out of band key, which needs to be transmitted over a separate, secure, channel .. the one most often mentioned in the bluetooth spec for that is .. NFC.
I think NFC is going to happen. It's a complementary technology. I think it would dovetail with passbook (scan or wave the phone, same effect, subtract value from the same Starbucks card for instance). It's pretty free to put it in the phone, the chipsets have the capability anyway. There's a load of ways they can integrate it into the phone to add value and it opens doors for lots of applications.
Is it happening this year? That I'm not sure. When I first saw passbook I figured one day NFC was coming to pair with it, might be this year.