Ask HN: Why music streaming services have identical pricing?

Got a notification from Spotify that the cost of my subscription would increase so I went and checked out alternatives. Was surprised to see that everyone charges £16.99 / month; sources:

- Spotify https://www.spotify.com/uk/premium/ - Apple Music https://www.apple.com/uk/apple-music/ - YouTube Music https://music.youtube.com/music_premium - Tidal https://tidal.com/pricing

Looks like there's price collusion, how are they getting away with it?