I almost did. I earned my black belt in karate and was teaching a few classes per week. I had frequent conversations with my sensei about working full time for him or starting a dojo of my own. We had a location picked out and everything.
Martial arts can be incredibly fulfilling. I got to help people improve their physical and mental fitness, gain confidence, overcome anxieties and fears. There were constant opportunities for fun, new friendships, and doing good in the community. Plus it was really cool knowing I could do some of those Bruce Lee / Chuck Norris moves I'd see in the movies.
At the time, I was the sole income for our family (wife & 3 kids). The income possibilities were just not there. We could not have made it work financially. Now, I'm an old out of shape desk jockey.