I guess I'm not sure that there's a practical difference between "It's marketing" and "This is what the market rate is for a CEO." In other words, firms need to pay this much because that's what other firms are paying (at least.) That's not marketing - that's just the unfettered market at work. Which is why it needs to be fettered. I agree with the salary cap idea, because the market will naturally keep raising the price without bound unless there's something to counteract that, and it is terrible for the labor market as a whole (and even the company as a whole) to be paying so much for a CEO when the same amount could buy dozens or even hundreds of workers.