How come it's okay for a company to say they don't give me a raise for increased costs of living, but it's okay for a company to pay less, because I live in an area with lower costs of living?
Besides, your alternative isn't making more money. It's not getting the job.
Some of those characteristics were given protection in law after enough noise was made.
Of course any adjustment in pay needs to fit budget, so the company and line manager would need to have the budget to afford to. And there's probably plenty of companies that won't have this as an option or won't adjust for inflation, but there's also plenty of examples that do.