Music has always been a doubtful source of income for the musician. Bach and Handel needed their titled sponsors.
In popular music, there are always more losers than winners, always more dross then gold. The money there has come from the performer hooking up with an entrepreneur who has invested time and money in the expectation of big returns, of which the muso gets the crumbs from the corporate table. Of course there were still more flops than mega hits.
There are still people trying for the next big thing though, with the Gaga, Beiber, Talent show results that posters here rave about.
The thing that has changed in recent years with the widespread availability of the 'means of production' as Karl Marx has it, is that anyone now wishing to sell their music has to compete with those musicians who give it away free- and survive with those 'consumers' who steal it on a massive scale.
No industry can cope with that.
Music cannot now be an industry. I have always resisted the term anyway. At best it is a small business, creating and operating in niche markets.
For most of us though, it's a hobby, a wonderful, creative, rewarding and frustrating passtime.
Maybe I'm lucky in that I can live with that.