Musicians should be getting closer and closer to 100% royalties as the infrastructure gets cheaper and cheaper. But, tech CEOs all like crappy music. Which is why they should never be in control of the livelihoods of creatives.
The reason there are any royalties to distribute at all is that Spotify has managed to create a distribution service that ppl are willing to pay for.
You can get free distribution for your music easily. Just put it on any torrent site...