> I have vague memories that QuickTime used to come with the iTunes package for Windows, but I may be wrong on this so don't quote me on it.

It did, because QuickTime is/was a media handling framework. The article isn't talking about the QuickTime Player application except incidentally. When you were using the Mac on OS 7 up until about 2011 (with the introduction of AVFoundation), just about everything that was playing media using Carbon or Cocoa API calls was using QuickTime under the hood.

When Apple ported QuickTime Player to Windows, they ported the QuickTime framework, too -- and iTunes for Windows was built to use that. So QTP basically came along for the ride whether you wanted it to or not. I don't know if this is still the case, though.