Well first of all, Spotify is no panacea, artists and labels don't really like it but they have no choice because they need distribution in order to sell albums/concert tickets. Even the largest artists like Taylor Swift who has protested against low Spotify royalties only temporarily took some material off Spotify, and ended up putting it back because in the end she looks like the bad guy to her fans if they can't stream her on Spotify like everything else they listen to.
Netflix was originally hoping to corner the market in a similar way, and they had a good first step with the Starz deal in 2008. However video is different and those rightsholders had full view of what happened in the music industry, so they were not about to make the mistake of ceding all power to a middle man. By the time Starz deal expired in 2012 it was clear that Netflix could never get all content because rightsholders would not let it happen. Similarly, the industry realized they need their own distribution. So Netflix and HBO entered a race to become each other. Since then the technology has only commodified which has allowed more rightsholders to get into the game.
Is this bad for consumers? Sure, but "the industry" is not a monolithic entity, and they certainly will do everything it takes to avoid becoming dependent on a single distributor with too much power like Spotify. It doesn't matter how many angry nerds complain on the internet, these companies will continue acting in their own self-interest, and the market carrying capacity for streaming services is probably way higher than most consumers want to admit. The only thing that will turn this around is by services dying because people don't pay for them, and I don't see that happening any time soon.