The peters principle makes an assumption about the convexity of competency that I’ve never thought was great. Essentially someone could get promoted to their level of incompetence, when if they were promoted again they would actually get better at their job.
There is an implicit assumption that competence at job a is less than competence at a job b above job a, which isn’t necessarily true.
There is an implicit assumption that competence at job a is less than competence at a job b above job a, which isn’t necessarily true.