"Is it just me...or does anyone find it very strange that hardened martial arts masters are hanging around on a tech web site?"
I assume you're referring to the people who've stated they have some form of experience (a few of us above)?
Well, I never qualified (or tried to qualify) as a master, I just like the training, which I've been doing since I was a kid. It's a pastime, in the same way as people go running or whatever - jogging five times a week for 20 years doesn't mean you're an Olympic athlete, just like training in martial arts for 20 years doesn't mean you're a "Master".
Also, teaching as a F/T career doesn't pay very well unless:
a. you're very lucky
b. you throw "ethics" out the window and work on conning people with flashy tricks.
c. you lie about how much you earn whilst you're actually flipping burgers.
The people I know who make a full time living out of teaching do so because they enjoy it (and they consider enjoying their work to be the most important thing), not because of the fantastic money. Apart from the "big names", most of the good ones are on moderate incomes, which can fluctuate wildly from one month to the next. Not what you want if you're trying to pay a mortgage and raise a family, really. You also need to be a very specific type of person to effectively teach AND make a business out of it AND put up with all the shit from your students - or 'customers', as they are these days, who expect "service" in the same way as they do at a restaurant
For me, I don't have the patience - which is why I went into a career that rewards grumpy surliness...