It was never easy making a living as a musician. If you were really good, and at least a bit lucky, you could. The vast majority had to have other jobs.

I agree it's probably tougher today though. The fact that producing and recording is something anyone can do with a laptop just makes the S/N ratio even smaller. And a lot of the surrounding industry jobs have probably gone away too, since big physical mixing desks and multi-track tape machines and record cutting and pressing machines are no longer used nearly as much.