FYI:
You can make a decoder that is entirely independant of quicktime, and that is probably what they have done. I can't even guess why you think they have ported quicktime to the phone. They already have MPEG4 in there, that is probably as close to quicktime as you will ever get with it.
I don't get the big deal here, many new phones can play MP3.
You're not thinking about the box man. It's the DRM that's unique here not the fact that the phone plays music. Remember the DRM is embedded in the file but it is Quicktime that manages the policy. This is a lot bigger than many of you realize. QT with Fairplay DRM is ready to be licensed out and that's a huge step for Apple.
I don't rule out Apple making an attempt to make their own phone someday. If they do they will wait until they can provide a phone that would meet their standards for features/quality and a phone that covers a wide area. Phones seem to be in transition right now and it'll be a couple of years before things settle down IMO. Apple might be ripe for a nice product by then.