I have long wanted to build a combination of: Bandcamp, GitHub, and Steam for musicians.
Basically, a platform for musicians to produce music (and associated videos, artworks, etc), managing their assets securely, sharing and collaborating; then engagement with fans, promotion, merch, and touring support; and finally a simple platform for sales (streaming, downloads, and physical good) where the store takes a reasonable fee, but the bulk of the revenue goes to the creator.
I was kinda hoping Bandcamp would evolve in this direction, but I think that's not likely now.
Fond memories of Indaba Music cerca 2010
Outside the classical world, if you look at a site like Bandcamp, that idea seems core. The business model also seems exactly like what you are talking about, both for performers and for the site. I see a lot of very obscure, niche electronic stuff that is supported by hundreds of people. That may only be thousands of dollars, not tens of thousands. However, it’s an economy. And compare earning $10 for the sale of a single album to the number of streams you need to earn that much revenue. We are talking orders of magnitude difference.