Spotify broke their recommendation system earlier this year. You used to be able to turn on this feature and it would insert some recommendations into your list. You could add them or delete them and then turn off the feature. So you could update your playlist with a few new songs. Now, you can't do that. And for some reason, it's de-emphasizing songs that you added to your list.
I'm wondering if their recommendation algorithms are too much like the humans that wrote them. In my experience, few people have eclectic musical tastes. They get stuck on one genre of music and to them everything else is garbage and ripe for ridicule if someone else plays it.
But it's certainly WAY better than SiriusXM.