I'll give Apple a couple years to bring more content providers into the QuickTime world!
Real Networks has already established its products as the standards for video/audio in realtime, but this will change. IBM and SGI are also working on bundling QuickTime Servers on it's Enterprise servers.
Well, QuickTime stil has to mature in the real-time video/audio arena. Let's hope QuickTime 4.5 brings some kick ass M-PEG 2 support, better frames rates over 28.8 modems, and the promised Speech recognition over IP. Many people doesn't know about this feature, but it was there in early alphas of QuickTime 4, but I wish I knew what happen to that feature in the final version!