Teachers' roles in learning and teaching

Perhaps this topic is very familiar. However, it is hard to be understood and fulfilled.
First, teachers find it very difficult to write a curriculum as they think they are supposed to "teach", not to "write" a curriculum. They think they should not do it. Instead this should be done by textbook publishers. Then what are the meanings of school based curriculum development?
Second, teachers feel that they burn out because they are asked to do the tasks that their "bosses" like. But what do their bosses like? Do they know what they are indeed?
Third, teachers protect themselves and question their students' abilities by saying "why are my students so slow?" They don't question why they are so fast.