At the other end of the spectrum, CEO's salary aren't that much a secret, which I read somewhere that is precisely the reason why their salaries are inflated. If CEOs know that other CEOs are paid that much, they are likely to request the same amount of remuneration, or even more.

CEO salaries are inflated because they're buddies of the people who decide what they pay, and they're all working to help each other out (and have the favor returned). It's a lot simpler than that.

I would argue this is the fundamental difference between middle and upper class. If you're middle-class, you get what your labor is worth on a market. This may be $500 for an hour of work, but your compensation is based on a market value. If you're upper class, you get what your friends will let let you suck out of the system, through executive and board-position sinecures.