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.
I dunno about that. I knew several tae kwon do folks back in the 90s charging around ~$300/mo subscription for twice a week class lessons. There would be 3-4 sessions m-f with 15-25 kids each session. I think the dojo was pretty financially healthy. Uniforms ran like $70-100, iirc. This was in central new jersey. These friends were financially, pretty comfortable.
Now I have my inlaws teaching taekwondo in rural Michigan and that’s definitely not a profitable endeavor. More a labor of love.
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.