The difference is that in most other industries these people get weeded out, or forever trawl along at the bottom. In aviation however these people seem to have a very easy and quick path into management or even CASA. I bet that there is not a person out there who can't name at least two people that have 'made it' or ended up in CASA who are complete failures as decent trustworthy individuals.
Reminds me of the old saying about politicians. Those who would be best at it are the very people who are not the slightest bit interested in being one.
At the risk of tarring some very good people with the same brush, to a certain extent this also applies to many in govt departments. Many end up there by virtue of the fact they havent succeeded elsewhere in the industry.