Well said! Teacher are easy targets to blame, for the quality of education. People don't realize that teacher's hands are often tied by the system. Some systems have timetables for student progress, that don't allow time to make sure the student's learn. They are concerned that the information was taught.
Never mind the outside forces that interfere with a student's ability to learn (poverty, hunger, homelife, etc.) With the focus being blame the teacher, it easy to see how teachers can become, depressed and hopeless, Teachers need to remember they can choose how they react to be the scapegoats.
Not forgetting to mention that teachers are expected to be family mediators and social workers. Should the child come a certain family background, we are expected to provide support that would remedy the difficulties put on the child by their families. How we are supposed to do that I don't know. I am still trying to figure it out.
There are many factors at play regarding a child's performance, as you've stated. But at the end off the day all fingers point to the teacher. It's no wonder why such a noble profession is in thee state that it is currently in globally.