The ruling elites setting the wages had historical precedent from Roman times. One of the emperors, perhaps Diocletian (someone here probably knows) decided that the classes should be made rigid, like the Indian chaste system. It destroyed the economy as people with any ambition were totally shut down and impoverished.
I doubt that it was Diocletian, or any of the later western emperors, as the economic life of that part of the Roman Empire was actually pretty great during the 3rd c, thanks to the political fragmentation. Diocletian did introduce the practice (echoed today in the vesting of priests when the Pope does it) of supplicants prostrate with their arms over their heads when making their case with the Emperor. That was the way it was being done in his time in the various eastern neighbors.
The rigid class system in ancient Rome was already in place during the so-called republic; it was a real problem for people in lower classes, and it had to go. The hereditary despots from the assembly of despots known as the Roman senate fought tooth and nail against it.