What is peter principle in management ?
The Peter principle states that a person who is competent at their job will earn a promotion to a position that requires different skills. If the promoted person lacks the skills required for the new role, they will be incompetent at the new level, and will not be promoted again. If the person is competent in the new role, they will be promoted again and will continue to be promoted until reaching a level at which they are incompetent. Being incompetent, the individual will not qualify for promotion again, and so will remain stuck at this final placement or Peter's plateau.
https://en.wikipedia.org/wiki/Peter_principle