The truth is most flight schools are not profitable. The last flight school I worked at was fairly busy for an operation that had two planes and two CFIs, but at the end of the month, we were lucky if we made a $2,000 profit. The manager of the flight school didn't take a cut out of the flight school because he was also the manager of the entire airport and viewed the flight school as a way to keep the airport alive, get students to buy planes from him, and sell fuel.
Now if he was not the manager of the airport, that $2,000 profit would have been his pay which would be pretty low. Between the cost to run a flight school and the lack of customers with the necessary disposable income, there is not much left over to pay for labor.