Way back in the day when I worked on the bus side of pre-TfL LT my boss invited me to a "meeting". I declined as I don't believe in self-advancement through dubious methods. It certainly explained how he had got promoted beyond his abilities!
Yes, quite a few fitted the above description! Conversely, there were many in my time who were probably well capable of doing a good job, but were either constrained by their not being given a meaningful role or, if they had a decent job, chose to devolve it to their subordinates and spend all day socialising! I had one of the latter for a while when I was a trainee and, nice man as he was, he was a useless employee, but he couldn't have cared less! He had a 'job for life' and free travel throughout London too, very useful when you lived in Elm Park!