To that I would add, most writers are perpetual amateurs, in the sense that you never know if you'll get a penny for the book you're working on until it gets accepted for publication. And even then, whatever advance you get from the publisher is probably all the money you will see, since it's the rare bestseller that stays in the public eye long enough to produce much in the way of royalties.

I'm finishing my MFA next month (at 69) because I wanted the boost to my craft. I love the feeling I get from writing something that I know is good. But earning a living is also nice, and to earn a living writing would be uber-cool. That's why I'm stoked to see real money coming in from writing CNF on Medium, since it will let me live the good life (meaning eat daily and sleep indoors--expensive habits both) while courting publishers for my poetry and fiction.