How did 'wieldy', the positive form of 'unwieldy', come to be a non-existent word?

I.e., is there a known reason behind why the negative form of the word 'wieldy', 'unwieldy', is so vastly used, whereas the positive form is essentially a non-existent word — MacMillan Dictionary doesn't even have an entry for it and the spell checker of my current browser is giving me a red squiggly line underneath that word?

The various on-line dictionaries I've consulted say 'wieldy' means 'easily controlled or handled', 'capable of being wielded easily' (e.g., wieldy weapon, wieldy car, ...), and, as such, I expected that word to be common among native British or American speakers, but Google Books shows (only) 20,600 hits for it and 1,500,000 hits for 'unwieldy'.

A bit of reflection should show that a commoner attribute makes for a less common word. Flightless birds are in the minority, so the adjective is needed; in most cases the term for flighted birds is just birds. A hammer or sword is designed to be wielded, so is expcetd to be wieldy; only when particularly large or badly made is it unwieldy, and hence worth remarking on.

I have heard the verb "to wield" referring to handling a sword or weapon, and wieldy (adv) is just the adjective. I would assume more attention would be paid to an unwieldy object, since a "wieldy" object would not need the same reference as being haphazard.

Wieldy

• Easily handled

I think this word choice is perfectly correct, according to the Oxford dictionary, although not much in use.

Etymologically, "to wield" means "to have power upon, to possess", more than it means "to hold a weapon or a tool and being able to use it".