I wonder if it's a bit of a vicious cycle. For example, if you only ever listen to new music that Spotify gives you then at a certain point, the algorithm only knows how to output the things that it has already outputted. If you don't give it any new external signal then it doesn't have a good way to find new songs.

> the algorithm only knows how to output the things that it has already outputted

That's a very old problem that people building recommendation systems solved 10 years ago.