Unfortunately, the way our modern economy works, your point seems logical. But it is not in line with Catholic social justice teaching. Yes, some jobs require more skill and will always be worth more to an employer. No one says that the market place plays no role in defining wages. But a just wage is a living wage, period. If a business cannot justify paying its workers a living wage, then it really should not exist. If people took that attitude, then the market would actually work better.

What part of my post is not in line with Catholic Social teaching?In the great words of Leo XIII in his wonderful encyclical Rerum Novarum
“Doubtless, before deciding whether wages axe fair, many things have to be considered; but wealthy owners and all masters of labor should be mindful of this - that to exercise pressure upon the indigent and the destitute for the sake of gain, and to gather one’s profit out of the need of another, is condemned by all laws, human and divine. To defraud any one of wages that are his due is a great crime which cries to the avenging anger of Heaven”
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“Now, were we to consider labor merely in so far as it is personal, doubtless it would be within the workman’s right to accept any rate of wages whatsoever; for in the same way as he is free to work or not, so is he free to accept a small wage or even none at all. But our conclusion must be very different if, together with the personal element in a man’s work, we consider the fact that work is also necessary for him to live: these two aspects of his work are separable in thought, but not in reality. The preservation of life is the bounden duty of one and all, and to be wanting therein is a crime. It necessarily follows that each one has a natural right to procure what is required in order to live, and the poor can procure that in no other way than by what they can earn through their work”
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“Let the working man and the employer make free agreements, and in particular let them agree freely as to the wages; nevertheless, there underlies a dictate of natural justice more imperious and ancient than any bargain between man and man, namely, that wages ought not to be insufficient to support a frugal and well-behaved wage-earner”
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"If a workman’s wages be sufficient to enable him comfortably to support himself, his wife, and his children, he will find it easy, if he be a sensible man, to practice thrift, and he will not fail, by cutting down expenses, to put by some little savings and thus secure a modest source of income. Nature itself would urge him to this. We have seen that this great labor question cannot be solved save by assuming as a principle that private ownership must be held sacred and inviolable. The law, therefore, should favor ownership, and its policy should be to induce as many as possible of the people to become owners. "