Capitalism and fiduciary duty prevents employers from paying people their market value when they are content enough to stay.
An employee who does not do the effort to re-peg their labor time to market rates for their skill level is implicitly consenting to a prior agreement (when they were hired).
Funny how fiduciary duty in these contexts is overwhelmingly short-sighted.
That is an extremely short-sighted view on what is essentially an iterated game where the domain knowledge employees have drastically increases their value to the company over time.