Why are jobs that are needed the most paid the least? That is some sort of manufactured contradiction. If they are paid low because they are easily replaceable,

Why are jobs that are needed the most paid the least? That is some sort of manufactured contradiction. If they are paid low because they are easily replaceable, why are they the most needed jobs? If they are paid low because they aren't needed, then they aren't needed and shouldn't exist. What could a third possibility be for these jobs being paid so low, i wonder? He said, facetiously knowing the answer