That ship sailed in the 90s with widespread music piracy. The market simply doesn't value digital copies of recorded music that much anymore.
Spotify was an increase in artist revenues as prior to that most people were paying nothing for their music, be it bittorrent in the 00s, cd copying in the 90s, or recording radio to tape in the 80s.
The problem is that people don't care about "all the music ever recorded". They mostly care about a very limited selection of music. And if Spotify starts costing like $45 a month, how many people still think it's worth it? You can buy like four albums off of iTunes for that and then listen to them as much as you want.
For all music ever recorded, maybe. But Spotify doesn't even have half of what I'm regularly listening to - a regular annoyance - let alone half of all music ever recorded.