If I'm not mistaken, 'play on demand' in this context is a backronym[1]. The iPod name is apparently a reference to 2001: A Space Odyssey:
> 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]
Thanks for article - possibly it's 'retcon nonsense' but the explanation of 'pod' preceding 'iPod' was told to me in the very early days of iPods so if it was made up then it was made up nearly 20 years ago.
> 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