Those playlists become popular because of the music on them. If they decline in quality won't people will just listen to better playlists?
My Discover Weekly from Spotify used to be awesome. I found a bunch of new artists that I really liked and tons of great new songs. Recently it's been a bunch of old stuff that I've definitely heard of before. So I've mostly stopped listening to it.
Discover Weekly went from something I was excited about every Monday morning on the train, to something I forget to check most weeks.
There's a handful of songs it puts on every few weeks, for literally years now, despite me skipping them every time and never once listening to the band or song by choice.
My Discover Weekly from Spotify used to be awesome. I found a bunch of new artists that I really liked and tons of great new songs. Recently it's been a bunch of old stuff that I've definitely heard of before. So I've mostly stopped listening to it.