In a hierarchy every employee tends to rise to his level of incompetence. Members are promoted so long as they work competently. Sooner or later they are promoted to a position at which they are no longer competent, and there they remain. In time, every post tends to be occupied by an employee who is incompetent to carry out his duties. Work is accomplished by those employees who have not yet reached their level of incompetence."
(Lawrence J. Peter
/ Raymond Hull, The Peter Principle)