Have you ever been a c-staff? C-staff are employees as well. Usually more expensive employees. Well run companies are trying to figure out how to win in the marketplace. To do this they hire the employees they need to win. Investors do this with CEOs.

I agree that it is much more difficult for a CEO to get fired than a line employee as CEOs have significant influence in picking their boarda. However, the consequences to a company of replacing a CEO are generally more significant as well.