Without any personal experience _exactly_ like yours, you may well be
right. I find myself re-reading books and re-watching movies that I have
read/watched less then some ten years ago, and having only a faint idea
- if any - of what will happen next. The good thing is, off course, that
I don't have to buy any new books, I've still got lots to re-read. OTOH,
when listening to music (which I used to do a lot), I can normally tell
the development of the song or the piece quite right away, though I may
not always remember the artist or composer.

An additional (and more likely?) explaination in "our" cases may very
well be that when we saw a show/movie/read a book, that was usually a
one-time-experience, while you may have heard the music from the show
several times during the last 25 (?) years, consciously or not, as I
probably will have heard some musical pieces tens or hundreds of times.
It just ought to get stucked, then, doesn't it?

Apart from that, it may also very well have something to do with our
brain wirings.

All in all, I don't have a clue :-), but like you, I find it interesting.

rgds, ole k
generally having a hard time remembering anything at all :-)