Scott Adams had a take on that. The "Dilbert Principle" (his version of the Peter Principle) is that useless engineers that are promoted away from doing real work to keep them from messing it up.

I have a much darker hypothesis about it - when people are left to compete, they often resort to badmouthing those who they think could outcompete them.

Thus, the reputation of the most competent gets destroyed, while the village idiot remains as the only one left unscathed.