Earlier quoted context omitted.
* like bookstores and coffee shops and art galleries* Also, martial arts schools.
I taught martial arts for a couple years fully knowing I'd lose money in the process. How did I know that? Because my sensei had told us that he didn't make any money either. Neither does his sensei. I think at this point is almost a rite of passage - if you want to teach you do it because you like it, not because you expect to profit from it. Of course, the economics of your area also apply.
A reason for getting into sports coaching is the same as for any other addiction, you reduce your own costs by becoming a pusher.