@joyR
That isn't a profession, that is a hobby
No, that is a profession. A few years back he was about to be called up to the majors when he needed Tommy John surgery. I believe the minimum salary for the majors is around $600,000/yr.
For many professions, such as baseball and actors and authors, it's the big ticket that they hope to get that keeps them going and sacrificing. But until they get it, if they ever do, they are still professionals.
Merriam-Webster has several definitions, but this one caught my eye:
participating for gain or livelihood in an activity or field of endeavor often engaged in by amateurs
"Gain or livelihood." Gain simply means to make money doing it. "Often engaged in by amateurs" means anyone can do it, such as play a baseball game in your local park with your friends or even compete against other teams, but not for monetary gain. And then there's the "semi-pro." Those people are still professionals (get paid) but not with the same status.
So it's the same with authors. There are many authors on SOL that do not write for monetary gain (amateurs). But some do (professionals).
Are all of those who write for monetary gain professional authors? One could argue that if their product is not of professional quality, then they are not professionals. Or if they don't run their writing/publishing as a business, they are not professionals. Or one could simply say that if they get paid for their work they are professionals. That used to be the difference between amateurs and professionals in sports. Monetary gain.