DF - it is known as the 'Peter principle" - and you are correct - She is dumber than a bag of hammers and "does not comprehend"!
https://en.wikipedia.org/wiki/Peter_principle
The Peter principle states that a person who is competent at a job will earn promotion to a more senior position which requires different skills. If the promoted person lacks the skills required for the new role, they will be incompetent at the new level, and will not be promoted again. If the person is competent in the new role, they will be promoted again, and will continue to be promoted until reaching a level at which they are incompetent. Being incompetent, the individual will not qualify for promotion again, and so will remain stuck at that final level (termed "Final Placement" or "Peter's Plateau"). This outcome is inevitable, given enough time and assuming that there are enough positions in the hierarchy to which competent employees may be promoted.[2] The "Peter Principle" is therefore expressed as: "In a hierarchy every employee tends to rise to his level of incompetence."[3] This leads to Peter's Corollary: "In time, every post tends to be occupied by an employee who is incompetent to carry out its duties."[4] Hull calls the study of how hierarchies work "hierarchiology."[5]