The price of everything is always between the value placed on it by the buyer and the cost to the seller. Not a revelation.

At the margin, they are all equal because trade continues until the gains from trade are exhausted.

In many countries and U.S. states, laws guarantee that the cost of an employee to an employer is almost twice as much as what the employee is paid. In those circumstances, the potential gains from bilateral trade are not exhausted and people engage in that trade outside of the dominion of the state.