I don't disagree that it's silly but the common misconception is that salary is based on some kind value exchange, it's not. Salary is the minimum amount of money it will take to get someone to work for you. Of course there are exceptions, but most salaried workers are not the exception.
Maybe that price gets driven up because of HCOL, or maybe it gets driven up by market competition, or skills scarcity (putting the employee in a position of bargaining). But it also gets driven down by the opposite effects. In the global market there are people with lower costs, lower market competition, but the same skills, and they are going to accept a much lower amount.
Take insane wages in SV as a great example, HCOL causes people to not accept lesser amounts, as does market competition. The fact that someone is getting paid more in SV is not because they add more value, it's because they won't accept any less.