[closeparen]

Competence is a continuous spectrum. People in its upper reaches are disproportionately likely to have already moved to talent hubs where their earning potential is highest, or to have acquired their competence working at companies there (and put down roots). Because they are still in talent hubs & have access to those markets, you cannot get them for less than talent-hub pay.

So you either: a) write off every candidate who is still in talent hubs, b) pay way above everyone else's competing offers so that your universal salary is also competitive in talent hubs, or c) pay based on location.