Reading about whether our younger generation is getting ... less smart since the incentives of teachers are all messed up makes me wonder more and more.

Why not use a trivial way to shield teachers from angry parents of not-so-bright kids?

The way I proposed many many years ago, and the way a few (more totalitarian, sigh) regimes are quite happily adopting.

The solution is to separate the teacher from the one who evaluates the student and grades them.

A really trivial idea. And for subjects such as maths, the test can and absolutely should be a) universal, and b) non-reproducible, i.e. not something one can memorize.

Simliar to how language tests are passed. The kid (or a university student) is obligated to show up any time during some wide time window and take the test. The test is taken on a computer in an empty room, phones not allowed, cameras everywhere. No room for cheating. And no room to blame the teacher later on.

In this model the teacher — or, if you wish, the professor — is literally 100% on the students' side. The teacher can not possibly optimize any metric other than their students' ultimate score; and the teacher does not even know what the questions will be this time. So, the only incentive for the teacher is to, well, teach.

And in a few years, literally single-digit, we will know who are the better teachers. Schools will make them offers. Parents will chase them to have them as teachers for their kids.

A total and absolute and unconditional win for any society that does prioritize quality of education. Which, unironically, does not appear to include Western societies these days.