If not, it doesn't matter what the facts are from management's POV, it will lead to the same effect on trust & morale. Most people believe they are high performers and the work that they do for the company is valuable; if they didn't, they probably wouldn't do that work. If you have a workforce who believes they are all solid performers and then they have to confront the fact that management believes one of them is 10x better, you've got a recipe for a toxic culture.
That's a major part of why I consider open salaries to be a terrible idea for top performers. Performance and popularity are frequently uncorrelated, and I'm not talking about the asshole genius trope. You don't want to force your best performers into allocating lots of time schmoozing to ensure everyone loves them and isn't offended by their higher pay.
Almost nobody thinks they're below average in performance, but mathematically some people have to make less than average.
https://news.ycombinator.com/item?id=15033386
Seems like management is damned if they do and damned if they don't. If they reward high performers in proportion to the value they generate, they kill the culture of the company. If they reward everyone fairly & equally, then all the high performers quit.
Full employment theorem for entrepreneurs, I guess. If management is rational, they'll never put the whims of one high-performing employee over the culture of the company as a whole. If that employee is rational, he'll quit and take his work directly to the market. This creates a fresh stream of new startups, each of which either has to be bought back for their true market value, or else becomes the new hot company that hires the masses and hemorrhages its high performers.