I bought my iPod long before the iTMS was announced. The thing succeeded because it was easy to use, manage, and it could store your entire music collection (well, most people's entire music collection.) There were other MP3 players with one or two of those features, but not all three. The iPod needed to be a success for Apple to be able to sell the iTMS (the concept that is), to the music industry.
Electric cars I suspect could have the same selling point (well, minus the storage of all music. On the other hand, I don't know, you could put a big SSD in each one I guess) - part of the point is that this tremendously complex confusing device should be a hell of a lot easier to maintain and - until self driving becomes standard - drive.