The assumption here is that salary is set by forces beyond the employee's control, and it's either fair or unfair. I would argue that everyone's salary is fair,

The assumption here is that salary is set by forces beyond the employee's control, and it's either fair or unfair. I would argue that everyone's salary is fair, b/c it's set at what the employee negotiated for. If you accepted a salary offer as-is, then that's what you get. If you feel your salary is unfair, then contact your boss and negotiate for more. I won't get into all the tactics of negotiation, but it works the same for salary as for a used car. It will help to have as much leverage as you can get, for example an open job offer at the salary you want.