I don't understand why people assume efficient markets. This is a good example of a market where I'd assume that the market is not efficient - there are poor i

I don't understand why people assume efficient markets. This is a good example of a market where I'd assume that the market is not efficient - there are poor information flows about CEO value; empirically, CEOs who are paid a lot don't often seem to steer their companies well; there are skewed incentives for the board since board members may very well be CEOs at other companies; there's very indirect shareholder control over pay; the company as a whole is unlikely to fail if they overpay since CEO pay is usually a small part of the whole budget, etc. Shouldn't you have to prove the surprising premise that the market is working?