[citadel_melon]

A perfectly efficient market doesn’t necessarily mean that a good is traded at its marginal price. You’re instead describing a perfectly competitive market. An economy is Pareto efficient (aka perfectly efficient) when resources are allocated such that no one can be made better off without making someone else worse off.

Even if I give into your premise — which I don’t — marginal price would differ for different careers, such as doctors who had to take on more education costs and opportunity cost and thus have a higher marginal price above bare sustenance.