Peter Principle
People in a hierarchy tend to rise to "a level of respective incompetence."
The Peter Principle, founded on research conducted by Laurence J. Peter, states that individuals rise through a hierarchy until they are not competent enough to rise further. It’s often understood as a cynical condemnation of organizational culture. Implicitly, it suggests that leaders are not competent for the challenges they face.
Naturally, some organizations make efforts to counteract the Peter Principle, for example by providing managers with training and continuing education.