Likely because most public companies are mostly owned by funds of one sort or another which either don't hold the stock long term or own the stock because of indexing. In the former case, the incentive is to select for CEOs who raise the stock price in the short term. In the latter case, there is no incentive for fund managers to influence management at all.
The discussion is why the board does not select cheaper CEOs. In the case of these supposed funds that are not interested in the stock long term, is the claim that a more expensive CEO will deliver them better short term results? If not, why would a fund that cares about short term results want to overpay for a CEO?
