Life ain't fair, and it's certainly not a meritocracy.

When you rise to power you can take better care to promote the right people. But according to what "right"? This is not a one dimensional problem.

Then we have the issue of 70% of the population thinking they are of above average competence.

...

That said, if it's a significant issue at your current work place I suggest you start looking for a new, better, place. And highlight the issue. People will get angry, and you might loose your job.