To be fair and to answer to your sarcasm, a KP should definitely step down IF teaching and management abilities are not up to standard. I am willing to do so if I know that I am not performing up to expectations. This also conforms to how the private sector is like - true meritocracy.

And to add on, looking at the other side of the coin, I will also definitely not want capable KPs or SLs to step down. I have seen some teams (I myself as part of a team as well) working so productively and happily under competent leaders before. When an experienced, capable leader leaves, the whole team ends up suffering or underperforming.

Unfortunately, I have not met many of such capable leaders. Most of the capable ones I know have left or resigned. Many incompetent ones are still around.