At least for metal, there are still tons of tiny musicians. Underground labels do cassette runs for the smallest of them, medium-tiny ones might get vinyls.

Bandcamp is chock full of bands, from home produced stuff, to bands spending saved money on a cheap studio. It's enough that even in the sub-niches I like, I can listen to 10-20 newly released albums every week.

I doubt more than a small single digit percentage of them make money that way, but they very often really enjoy what they are doing.