You don’t clear $50m a year by paying people what they’re worth. The wages are unfair, by definition, if there is someone able to skim away that much at the top.
Your definition of “unfair” is quite peculiar. By your logic, the same salary for the same work can go from being “fair” to “unfair” depending on how many employees you have.
No, it's as simple as income ratios between the lowest and highest paid employee in a company. Above a threshold starts to be completely divorced from their respective work ethics and general intelligences. It's more just an abuse of systems that have been built up over time specifically to allow for that level of exploitation.
Quoting supply and demand in labour is just insulting and indicative of someone maybe getting a bit too high on their own supply.