I can only speak for my little corner of the world, a Midwest town of about 80,000: I know most if not all the musicians in town, and every single one, including myself, make money playing music. For sure, this “for hire” aspect of making music limits in some way what you can do, but they still enjoy doing it. I’d say 90% of the music is doing cover tunes, and about 10% do mostly originals. Then, a fair number also do their own stuff at home simply for the enjoyment of it.
BTW – there are a few musicians from my town that have “made it” and done quite well, and I know them all personally: Steven Hunter (guitarist), Alison Kraus, Brian Culbertson, Chad Grey (of Mudvayne and HellYeah), and the late great Jay Bennett was a friend of mine and lived in Champaign. All of them have had issues with “creative control” but that aspect of self-determination I think can be found in almost every business, especially artistic ones.