Apple's responsibilities
Um, last time I checked Apple has a legal responsibility to maximise it's shareholder's investment. That means there has to be a sound business reason to licence it's technology to a 3rd party (technology that, after all, cost shareholder $$$ to develop).
Now, what would Apple have gained by licensing FairPlay to Real (or anyone else) ? At the very most it would have gained market domination of media format (AAC) and DRM technology, some licence fee revenue (possibly, but the margins are already so tight that Apple's barely profits from it's own online music store), and increased iPod sales (and iPods are selling faster than they can be made, as it is).
At the end of the day, there's no particular reason for Apple to open up the iPod to anyone else at the moment. Just because they are having a great party doesn't mean they leave the front door open for anyone to gatecrash.
No Real have got fed up being left out in the cold (anyone actually bought a track off their store ?), and have decided to forcibly break and enter the iPod party. Oh, and the iPod isn't 'closed' - it plays MP3 just fine thanks. Just that you need to use Apple's DRM - and Apple aint giving you it.
Apple's best move right about now could be to licence FairPlay to a competitor for Real, but one that somehow isn't directly competing with iTMS. Oh, and make sure Quicktimes wipes RealPlayer off the face of the planet.