Yes, Sky, I would think so, too. Conceptually, you need to master more than just one thing to be master of the set of those things, as in "Master of Ceremonies" and "Master of Arts." But in actual English usage, that distinction isn't strictly followed. There's only a "Master of Science," not a "Master of Sciences." It's probably because the terms for such academic disciplines are mass nouns to be begin with, as in the case of "Education," "Psychology," and "Engineering." They are grammatically singular but notionally plural. In any case, I wouldn't be surprised if the singular or plural form comes to be adopted not arithmetically but idiomatically, idiosyncratically--meaning that they were not given much thought to begin with.
This reminds me of the story of a foreign archeologist who, upon visiting the Oxford University campus in England, had wondered why the streets in the place were--and still are--so indescribably crooked. He had a profound impression that no one in his or her right mind could have designed those streets, winding and zigzagging and plunging and lurching upwards or sidewise any which way through plain, hill, and dale for no conceivable or rational reason.
The archeologist then set out to research the history of Oxford all to the way down to its ancient beginnings. Had some eccentric road builder or loony academic designed those roads by any chance? Had a builder of mind-boggling mazes been mistakenly chosen to build them? Not by a long shot, the archeologist was to discover after long, painstaking research.
It turns out that the routes taken by those roads were chosen not by humans but by beasts. In ancient times, the wild oxen of Oxford would graze for most the day and, when it was time for them to slake their thirst, they would wend their way down to the Oxford River in the simplest manner that animals would--going straight where there were no natural obstructions such as huge trees and sheer cliffs, making sharp detours where it wasn't possible to go headlong, going uphill or downhill as the terrain dictated, walking onwards until they were finally downriver to take their drink. The oxen simply followed their lines of less resistance for thousands of years, until the humans came and--not inclined to change the natural order of things--simply followed the crooked ways of the Oxford oxen!
As with the streets of Oxford, Sky, so with English usage and idioms--sometimes they have neither rhyme nor reason. Sic transit gloria mundi.
P.S. By the way, Sky, I understand that Oxford got its name practically in the same way--"Ox" from "oxen" and "ford" from the Old Norse word fjord, which means "a shallow part of a body of water that may be crossed by wading." The particular ford in this case is, of course, where the oxen had found it most convenient to drink.
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*This Latin phrase means, of course, "Thus passes the glory of the world."