While iTunes was required, it was free and there was no subscription or limitation on what you could sync to the device. Apple actually seemed to be generally anti-DRM at the time, launching the music store with DRM as an industry concession, but eventually removing it and even allowing users to download DRM-free copies of songs that were originally purchased with it.
It’s like it came from some bizarro universe where only apple allows side-loading of content, but Spotify and YouTube do not (so they can take a chunk of your revenue, and censor/shut out competitors).
> The name came from a freelance copyrighter who, after seeing the prototype, thought of the movie 2001: A Space Odyssey and the phrase "Open the pod bay door, Hal!"[2]
1: https://en.wikipedia.org/wiki/Backronym
2: https://www.pcmag.com/news/a-visual-history-of-apple-ipods