If you have a CEO who is currently stingy about making process improvements that aren't sexy and is focused largely on office politics and that's not what the company needs at the moment, promoting someone who has been down in the trenches is a great option. Conversely if a company is bloated and needs to tighten its belt to survive, you might want someone who can look at it as dispassionately as possible. Really you can't look at it in terms of good or bad ceo, but rather appropriate or inappropriate.
Maybe you could argue this is what they should be doing, but it's clearly not what they are doing. The vast majority of CEOs simply suck some of the blood out of the company before flying off an parasitizing another one. You say the other answers are snarky; I say yours is naive.
> Would you have paid someone twice his salary if you thought they could do better?
No, I would have paid a random engineer who didn't want the job 1/10th of the CEO's salary and gotten a TREMENDOUSLY better outcome.