The problem with your approach is that it is very easy to manipulate people when you permit a power/information differential like that. You end up saying "the slave is happy with the food we give him; why should we offer freedom?" -- when he's only happy with the food because you've been beating him for so long he's been conditioned into helpless appreciation of your scraps.
You feel you're making a fair salary? Well then what is the harm of knowing your neighbor's salary? Are you going to learn a new meaning of 'fair?' What's the harm in that? That's just updating your priors and giving you the ability to make better decisions with more information. (That anyone would choose to reject relevant information when making decisions is the height of absurdity.)
So in such a situation there's little upside. You already know you're not getting scraps.
But there's a painful downside in knowing exactly who the company thinks does worse work than their direct peers.
But it's often supposed to be, and so salary differences can hurt feelings just as much as if the correlation was perfect. Or they can hurt feelings because the actual reason for the difference is unfair.
>The only people who benefit from salary secrecy are employers, and they benefit greatly.
Is that always the case? Remember, in this scenario we have a detailed knowledge of equivalent position salary, we just don't know which of those thousands of numbers belong to our coworkers. How does that remaining ignorance hurt me in any notable way?
I'm not saying that hurt feelings should override important info, but if the info isn't important, and it's not about you, then maybe hurt feelings should be considered.
Let's say I'm playing a game of poker. I know what my hand is, but nobody else's. You are telling me that I am advantaged simply by knowing the odds associated with my hand.
Great.
Except my opponent across the table can see everyone's hand. And they are telling me I should go all in.
That's why anonymous info isn't good enough: it's only anonymous to the losers.
This is more like knowing everyone else's hands in blackjack.