An answer I gave to a different post addresses some of your comments. You are correct teachers (and schools) serve two (or even more) purposes. It is to teach someone how to do things, i.e. the teacher role and they serve as gatekeepers, i.e. make sure that they know enough to get this qualification.

I also agree with you that in an ideal world we would not need the gatekeeper role and tests would only help the students on how far along their learning journey they are. However, reality means we do need gatekeeping, we need to test that a student has sufficient knowledge to perform a certain task, because literally lives can depend on it, e.g. we would not let people drive on the roads without an exam or let a doctor operate someone without proven knowledge that they can do it.

Because of the gatekeeping requirements and the interests of students they will optimize for outcomes, that might mean they learn some subjects in depth, but it will also mean they learn some subjects with the bare minimum to pass (and that is fine).

Unfortunately the students who optimize for outcomes generally outweigh the students who want to learn (at least vocally). I think everyone who taught will be able to tell you that students are incredibly conservative towards changes, even if they improve their learning outcomes (give us recipe instructions, not try to get us to figure out things for ourselves), because it might mean more work.

And I agree that ideally (and practically) we should need much less carrot and stick, but saying we will never need them is quite unrealistic IMO.