I have a friend who has been a working musician with no side gig for over 20 years. He makes money in a wide variety of small band types (pipe & drums for funerals and parades, Jimmy Buffet cover bands for festivals, jazz groups for events, etc).

What I take from his experience is that the things that make him successful are the same as many other jobs. He’s dependable, competent, on time and has a large professional network.