That might be true if we had a perfect market, but that does not exist. In particular the board who decides the CEO salary is disproportionately made up from ot

That might be true if we had a perfect market, but that does not exist. In particular the board who decides the CEO salary is disproportionately made up from other CEOs and upper management. They have a self interest in keeping CEO salaries high. Moreover many also like to inflate the importance of upper management on company performance (which we see at every management level), which again leads to higher salaries. Finally, often CEO pay is regarded as a status symbol, which essentially completely disconnects it from market considerations