I switched to YouTube Music from Spotify years ago, but have friends who refuse to switch, my understanding is:

- The YTM UI just feels worse than Spotify

- YTM has no official desktop app

- Moving all your liked songs and playlists over is annoying

- The whole shutting down Google Play Music just to release Youtube Music did a lot of damage to their "brand mindshare"

- People think it just means watching music videos on YouTube

- Everyone they know uses Spotify and they like seeing what their friends are listening to and it's easier to share links to songs within platform