The writer of the essay internalizes the oppression of the education system as a whole, it is not only our urban schools, but she makes the wrong analogy and points the finger at the wrong people. The proper analogy is that of a prison and the teachers are prison guards.
The primary function of the classroom teacher in our schools is to take and maintain attendance of the prisoners. Meaning, if a student or group of students begin to disrupt the classroom, you deal with it. As the prison guard you have limited options, you exercise all of them and by the end of September you have exhausted all of them. Then you settle into your job description and try to survive until June.
The teachers second job description is to be feeble before their supervisors, the school administrators. The administrative layer that dictate to the teachers have long ago abandoned the notion that our schools are environments of learning; that is how they were rewarded with promotion in the first place. When bold new teachers enter the building looking to make an impact, they are very quickly shut down by the administrators who see any change as a direct challenge to their authority.
It is precisely these two factors which inevitably leads to the high turnover that categorizes the teaching profession. The teachers that remain are the ones who will carry out their two primary job functions to the detriment of our children and our society at large. Until our society addresses the social and economic issues that drive school systems to the leviathan that they are, it is hopeless.