I don't think this is only a problem up north.
During my odd life, I was an assistant teacher (read: unpaid intern) in both Rossford and Toledo schools.
At Rossford Middle School, I practiced under a teacher that shouldn't have been teaching. The teacher swore at students during class and called a student dumb for forgetting their pencil. Calling a student dumb is over the line, but in this particular case it was unforgivable. The student who was called dumb (among other things) was one of the few latino students in the school. She was a shy girl who was very kind. Seeing her berated was heartbreaking and led to me being expelled from teaching in Rossford.
The teacher? She continues teaching at Rossford and now teaches master-level students at BGSU and UToledo. Despite writing the school board and other school official concerning her behavior, she was promoted. I never heard from any of the school officials. I told my supervisor about the incident of the teacher berating the girl. My supervisor, upon returning to the school, stood outside the door of the classroom and heard the teacher say she would "hit a student with their bloody stump." Thankfully, my supervisor witnessing this incident allowed me to get full college credit for the teaching experience, as the university realized I was not in the wrong.
At Toledo? Well... that's another long story, but the basis is that the teacher, who was months away from retiring, would show up drunk to class.
The system is flawed -- and it's not just Detroit. I'd bet there are several students in Toledo who pass grades without the qualifications to move on. There is a lot that needs to be changed with the education system, and I'm not sure that anything less than a full reconstruction will work.