The parent body of almost any school has a wide variety of differing opinions. There is simply no way for the school to implement all the many ideas the parents have — as different parents in the school have different, and conflicting, opinions.
Furthermore, almost no parent pays the full cost a Yeshiva incurs in educating their children. A large portion of the cost comes from third-party donors (i.e. Tzedakah) as the tuition does not cover the full cost of the schooling.