Plus, and I cannot stress this enough, iTunes really was power pushing the iPod and Apple along. First, by truly binding hardware and software together to work together as seamlessly as possible. Second, by being able to purchase songs from iTunes store, and have it automatically appear in iTunes. And thirdly, and this is perhaps the most important bit, by forcing (and by forcing, I mean sometimes using the mob style of forcing) the record industry to play along. No longer did you have to know which artist belonged to which record company in order to buy music. No longer having to browse 4 or 5 different sites to find music. No longer did you have to convert songs, if you could even, to another to get around DRM to get all your music to play on one device.
So, yes, they did revolutionize the music industry.