> It's not repetition, it's the deliberate creation of a comprehensible perceptual model which lives in the sweet spot between trivial prediction and surprise

Exactly!

The sweet spot between repetition and non-repetition - I cal it evolving repetition (same base but minor different touches or changes that evolve the pattern over time) and having different layers doing it - keeps the listener intrigued instead of bored, still keeping the predictability but giving the element of surprise.