How is this for an opinion?
It sounds to me that security concerns are holding over-the-air transactional capabilities up. If that's true, I'd like to see Microsoft and the music labels push a little harder to overcome these obstacles. I just hope this isn't the case of a bunch of Luddite, worrywort copyright-absolutist attorneys standing in the way of innovative technology.
Go to http://blogs.zdnet.com/ip-telephony/?p=1210
to see what it is all about.