I think this is right. A lot of my favorite music finds ways to rotate what's repeating. It finds a balance of keeping the groove while still playing with the listener's expectations. But, to your point, if there isn't enough repetition, there's not enough to grab hold of. Obviously, it depends on what you're trying to accomplish, but for most applications, you want to give the listener engaged with your music.

Beyond, or beneath, song structure, I've noticed that experienced songwriters repeat notes in their melodies more often than people starting out.

mpv skips forward a minute with the up key (sometimes to keyframes by default, but not with flac it seems) and it surprises me a bit how often you can do that and the music doesn't change at all, or only changes slightly :/.