I would take up the challenge to this economist's theory that 'contribution == pay' like this:
Economists rely on the idea that markets have perfect information. But it is sort of an asymptote/limit that the economists assume reality would converge upon in theory.
However, some people (or entire industries) make _alot_ more money than they are worth. Why? Because they have better information about the market, they were able to take advantage of information, timing, or ignorance of others, etc. With a doctor, or lawyer, their performance is transparent and measurable: education, state license, records of cases, patient outcomes, etc.
With a CEO, it is much more of a 'buyer beware' environment. You probably don't have access to private records that could verify their value (contribution to society.) Why do CEOs negotiate highly favorable terms of their departure (golden parachute) before they even begin work? Clearly there are factors at play that are likely to be some type of circular justification of their worth. Most other people state their qualifications when seeking employment, they are usually hired with the expectation of performing to that level indefinitely with no extraordinary terms of separation.
Unrelated to the perfect information argument is just good old fashioned control of supply. i.e. why does a union worker make more money than a non-union employee doing the same work? Nothing against union workers, I commend your initiative. Economic forces are at play that do _not_ correlate societal contribution to pay.
So I think the 'contribution to society' correlating to pay is a circular argument, it may be true in general but it can also be a justification for unapologetic greed when it fails to actually correlate.