It’s not competition if everyone has exclusivity contracts on all the content. Take Spotify vs Netflix for example. Spotify will have mostly the same base content as Apple Music, Deezer, what have you. With Netflix… You don’t get any Disney movies, no game of thrones, you have to buy all of the services to get access to even just the content you want.
I’ve never felt I was missing out on anything with Spotify, as I likely wouldn’t with YouTube music either. Maybe some have less but it’s at least a very comparable catalogue across the board.
Weird thing about music streaming in comparison to video streaming is that music streaming services are all third parties. There’s little to no exclusivity in that market because the streaming services all license from the same sources. The big music publishers haven’t gone and created their own streaming services, but are (more or less) happily working with Spotify, Apple Music etc.
That’s simply not happening in the video streaming market.