I'm an engineer-turned-musician, so I went from making too much money to being poor. But at least now I like what I do.
So what does a full-time musician do, exactly? Well, in my case I play piano and sing, so I get hired out at various venues to play and sing. Bands that need a pianist will call me, churches that need a music leader call me - I actually pay the bills fairly well this way. I used to sing for an opera company but my heart wasn't in it, so I mostly do RnB/pop and Jazz.
"It is not the critic who counts, not the man who points out how the
strong man stumbled or where the doer of deeds could have done them
better. The credit belongs to the man who is actually in the arenas;
whose face is marred by dust and sweat and blood who strives
valiantly; who errs and comes up short again and again; who knows the
great enthusiasm, the great devotions, and spends himself in a worthy
cause; who at the best knows in the end the triumph of high
achievements; and who, at the worst, if he fails, at least fails while
daring greatly; so that his place shall never be with those cold and
timid souls who know neither defeat nor victory."- Theodore Roosevelt
April 10, 1899