Peter principle

A good dev may not make a good manager. In 1969, back when Americans still got promotions at work, a book was written on this circumstance though it likely did not use developers in its examples. Wikipedia says: The Peter principle is a concept in management developed by Laurence J. Peter, which observes that people in a hierarchy tend to rise to their "level of incompetence": an employee is promoted based on their success in previous jobs until they reach a level at which they are no longer competent, as skills in one job do not necessarily translate to another.