Manually copying mp3 files to a Nokia or Blackberry just didn't come close to cutting it, and any attempts by those companies to compete with iTunes on the desktop ended in miserable failure due to piss-poor software quality.
Sorry, not true. I had a large music collection, and did not bother with iPod in the early days (and when I tried much later, didn't like scrolling wheel). It did not work with OGG Vorbis, nor could it have any moderate amount of storage. My DAP had 40 GB: iRiver H340. This was around 2003/2004.
A statement like "Anyone with a moderately sized music collection depended entirely on iTunes" is ignorant to the point where I almost feel insulted.
At the end of the day, using an iPod and iTunes neither limiting nor locking-in.
I had a fairly big collection and I didn't. Just used a folder structure and copied stuff over to my flash mp3 player (it was maybe 1GiB, maybe less).