Well, it’s not exactly my basis misconception. It’s not my idea. :rolleyes:
I would like to know which century you are describing. 
Sixteenth and seventeenth centuries.
Your misconception is that the words Governor and Governess never had a similar meaning, when in fact they did at one time.
At any rate, the answer to “Language: Why?” is as simple and complex as “Because: Culture.”
I would prefer that you use the term “a misconception”, not “your misconception”. I prefer using “a”, not “your”, because it is less personal.
Honestly, if I really had known that they once meant the exact same thing, just male/female variants of the meaning, then I wouldn’t posted here, would I? :smack:
Really? Then whose idea was it?
Then it appears that it is your misconception, doesn’t it?
Nitpick: the guy doing the ducing would be a dux, “leader”. The word ductus is a passive participle, meaning “led”.
Somebody who follows the dux would be a ductus.
I picture a long line of ducti following the quacks. (Or their echos.) 