How are you supposed to keep the joy of teaching flowing if you are doing everything for free ? I'm genuinely curious what is your solution to this ? Assume tha

How are you supposed to keep the joy of teaching flowing if you are doing everything for free ? I'm genuinely curious what is your solution to this ? Assume that the teacher has a family and a limited time. It is more depressing to see people advocating working for free without giving a solution to real life problems that a teacher usually has, like say putting food on the table or paying for health insurance.