It is my experience that the worst 2-3 per cent of people can ruin entire institutions if left unchecked.
How will we decide who is the worst teacher? Peer review? Student review? Ask the parents which teacher's politics they dislike more?
I'm not saying it can't be done, but I am saying that it's unlikely to be done right.
That said, it is not unique to schooling alone. Bosses around the world have to address this problem as well. IDK how Elon Musk runs his "no assholes policy" in SpaceX, but he seems to be successful. Ofc, maybe his approach isn't scalable, who knows.
In general though parents should be the ones making decisions about their children. Teachers being judged by arbitrary beurocrats i.e. what we have now sounds obviously worse to me.
The whole political argument seems weak to me. I think most parents probably care about academics more than that to begin with, but if political homogeneity is important to a particular parent, why shouldn't that influence their vote?
If the education is subpar, the particular skills and knowledge that were missed can probably be picked up later as needed, but poor grades can alter the trajectory of your life in ways that are harder to recover from. So I'd expect parents who care more about the best possible outcome for their children more than being conscientious (which I honestly assume is a majority) to prefer those.
Also - if it is impossible to detect bad teachers, then it is impossible to hire good teachers and therefore they are hiring at random. And parental choice can't be worse than random or that would be a signal we could use to pick the best teachers.
I will give you that teachers know who the other bad teachers are.
Unless teachers happen to spend their days sitting around in other teachers' classrooms, I highly doubt that's the case.
Teaching is not collaborative work, and I would not be comfortable giving a peer review to someone who I never interacted with, outside my lunch break.
They do, however, have a pretty good idea of which other teachers they personally don't like.
This feels like an assumption to me.
My wife is a public school teacher. There has always been heavy collaboration between her and her colleagues, even more so now with remote learning. There are certainly unmotivated and lazy teachers and the other teachers know who they are.
Parents are on average stupid. So are government officials. Centralising the power just means that when there is a bad official, everyone suffers. Just because the best alternative is still bad doesn't mean there is a great option here. All the choices have drawbacks.