Fully agreed that the notion that pay is (or should be) a deterministic function of a couple of visible variables is ludicrous. But knowing the range can be use

Fully agreed that the notion that pay is (or should be) a deterministic function of a couple of visible variables is ludicrous. But knowing the range can be useful, since you can also have a qualitative sense of how productive you are and how much weight you pull relative to most others at your level. Obciously you might be over- (or under!) estimating your ability, but that's something you need to resolve regardless, and a rough sense of where you fit in the salary distribution is independently useful.