Long-timers are survivors. When I started playing live, it was Rosemary Clooney, Marty Robbins; followed by Bill Hailey and the like. The mix was standards, country getting airtime on standard AM and rock-n-roll.
Then, there was the British invasion, followed by the influence of South American sounds. Add folk, disco, the cutting back, where first horns, then bass players, then drummers disappeared.
That was followed by the invention of restaurant licenses, where music became a side-line adder; not the draw, but a little diversion, followed by a corresponding cut in pay. Every little corner restaurant has music; usually a single acoustic guitar playing three chords.
That was followed by places that paid the musicians the door or less.
For me, the critical element of survival has been diversity, both in the aspect of playing lots of styles and a variety of venues; many not public restaurants and bars. I'm talking philharmonic organizations, jazz arts societies, recording projects...the list is long and varied.
I've done all of the above, and even though I know I'm a short-timer now, I'll have to make adjustments before I hang it up.
Sounds hackneyed, but hard work and talent will assure success; however it is defined in the future.
Good luck to all!
Russ