AnotherGuy
Hero
A couple things on this:
1) In the course of human history, monetizing a martial art, a craft, the product of artisanship is an extremely recent occurrence. Its a minor blip in the overall arc of millions of years and even when you index it to the Homo sapien record f the last 100 k years. Overwhelmingly, martial artists, craftsfolk, artisans plied their trade as a specialist among a small collective; an individual answer to a selection pressure....an answer that they handed down generationally among their clan.
2) Even in the last 10 to 12 k years where trade actually became a functional part of human history, martial artists, craftsfolk, artisans who actually monetized their trade is extremely small % of the total collective of those who are functional.
I'm not special, but I'm functional or better at probably 2 dozen things that I could effectively monetize. The world is made up of people who have broad aptitude at a number of things (sufficient to be "functional") but could never enter the tail of the human distribution in any one thing (like myself...I'll never be a world class anything, but I'm functional to good at a lot). These things would be "hobbies" to me (just like TTRPGing).
Do you believe the percentage of sports players, artisans and craftsmen who monetize their skills over the entire population are likely to exceed the number of functional GMs over the entire roleplayer community?
Furthermore
Sport is introduced as school level. It is prominent at college and university level. Furthermore club level exists. Participating in a sport could be beneficial for one's health.
Exposure to martial arts is prolific in movies and pop culture. It is valuable skill for self discipline and self-defense. Participating in a martial art could be beneficial for one's health.
Crafts and the product of artisanship are generally valuable skills to have.
Roleplaying is a useful tool for a handful of things many of which could just as easily be gained through any of the above activities.