Why are bad managers almost never fired/demoted?
Please, only answers from managers with at least 5 years of experience!
In my career I had the luck of having some exceptional good managers and some really bad managers. (I have technically always been an individual contributor, although I sometimes lead teams for a project/work-stream.).
Before we start, IMHO there are 'objectively' bad managers/bad management (to differentiate it from personal opinion).
Really bad management IMHO is objectively shown, when all members of the managers team leave the company/team, nobody in the company who knows the manager would volunteer to work with the manager (thus, a good sign is always, if a new manager gets a team mixed of people working at the company or only new hires).
I am a knowledge worker, and when people leave a company/team, the damage can easily be several 100Ks for new hiring, teaching the people and the months before the people get ready to work.
I experienced several times, that whole teams or half the seniors of a company left, because of obvious bad management (I am living in a country, where job hopping is not that normal).
Two times I observed consequences for the managers: Where half of the seniors left, one of three involved managers was fired. One of the places, where again most of the team left the companies or moved to other positions inside the company, the manager got demoted back to an individual contributor for a few months, and then went back to management with fresh/external hires, and this manager was comically evil (stole the work of the team and presented as his own, told white is black lies to his managers and got caught doing this, attacked people in the team which wanted to do constructive work with verbal abuse in front of the team).
Right now I observe again a manager which is comically incompetent and I know that half of the team is looking for another position/new job, and the damage that the manager did over the last years in demotivation is obvious. Another way to objectify this is, that it seems there is usually a broad consensus, who is a good and who is a bad manager between ICs, but I just went for the 'so bad, people leaving' metric, because this is really measurable.
What I simply do not understand: If I do not do my job, or if I would lie to management, I would be immediately fired. Observing managers in small and big companies, the opposite is true: Only taken the 'loosing half of the team or the whole team metric' (to objectify bad management), the managers fail badly, create reputation and monetary loss, and the default seems to be they are not being fired but get chance after chance.
Excuse the length of my question, but English is not my native language and I don't want to use a LLM to formulate.
So: Why are bad managers almost never fired/demoted? Why seem the higher managers in a company not to have any interest in identifying and firing bad managers?
Any insights highly appreciated!