I don't think that's necessarily true. There were many millions of people using Macs and many of them were intensely, religiously loyal to Apple, regardless of

I don't think that's necessarily true. There were many millions of people using Macs and many of them were intensely, religiously loyal to Apple, regardless of the technically (de)merits of the system. Launching a new OS as an upgrade to that massive install base is very different than trying to take a high-end workstation and turn it into a mass market product. And it's an interesting question how much that pre-existing Apple user base was instrumental to the success of the iPod.