Is the hypothesis that _most_ managers that get promoted are incompetent, or is the question really "Why do any incompetent people get promoted?" Easy enough t

Is the hypothesis that _most_ managers that get promoted are incompetent, or is the question really "Why do any incompetent people get promoted?" Easy enough to quote dynamics / principles that might lead less capable people to more often be promoted (managing up, kissing up, some Peter principle-related skill limitations) but at the same time as in any field most managers will fall in the middle between excellent and abysmal, and probably be "just OK." So maybe a simple answer is that the "mean" manager is below our expectations, therefore most managers will be below our expectations?