How do bad C-Suite leaders, end up in C-Suite?

For example: I work at a company that was relatively good at running without the President. I’m convinced it’s because we have an extremely good VP, who was I suspect was actually taking care of things.

The President was the great discourager. He was a walking, talking HR incident. Regularly said really inappropriate things about protected groups.

Eventually, the CEO “invited him to pursue opportunities elsewhere”. The new President is good.

How do people like my old President manage to get into C-Suite?