The iPod enabled the iPhone. The iMac saved Apple, while the iPod made Apple. Apple would never be where it is today without the iPod. It was that original..at least beyond the IXI out of Britain circa 1979...which never sold. The first commercial mp3 player didn't arrive until 1996..and only a rough 25 were sold.
So the iPod really changed things up large by creating an entirely new market... commercially.