Musicians need to force Spotify to raise its price to consumers substantially, or if that can't happen, then frankly, they need to drive Spotify out of business. As I said, this is an existential risk for recording artists, so it may be a choice between Spotify going out of business or recording artists going out of business.
Streaming services are too cheap. The price of buying one album is approximately $10, but for the same price a consumer can get practically every album in the world for a month on Spotify. That's not sustainable for musicians. Their music is being given away for peanuts. It's a race to the bottom, and it has to stop. It's not a matter of how to divide up Spotify's pie, because Spotify is only a mini-pie, and that's not enough to feed everyone. They need to bake a bigger pie.
It was never clear that Spotify and Apple Music were in the interest of the music industry. And you can see in the film and TV industry that the studios are pulling their content from Netflix and moving it in-house, which forces Netflix to produce their own content. Spotify and Netflix were clever in taking advantage of cheap content, and the industry was slow to react, but now there needs to be a counter-reaction to the fleecing of artists.