Jphone, I realize you meant the yeshivos, and that’s why I asked if you volunteer to do this. That’s basically what teachers are- volunteers (sure, they’re compensated for travel time.) Many capable teachers cannot afford to volunteer, so they don’t teach at all (except their own children) or don’t teach in our yeshivos.
Take, for example, you, Oomis, Jothar, and probably some other posters hanging around here.