>>/8700/
> That's right, and no I don't exactly have an explanation, it's just how I see it in my head.

I get this. In my old forays in writing I would have  sometimes manic  arbitrary choices and things I would like to stick to just because. 

> There's enough magic for a few unicorns do levitate things, but the land isn't saturated. 

If it wouldn't spoil the setting, is this due to some sort of cataclysmic event, or just a way to wink wink nudge nudge this is Equestria in the far future kind of deal?  

> plainsbillies

I am going to add this word to my vocabulary!

 >>/8703/
> Trying to autisticly resist googling the etymology of unicorn in a attempt for some harebrained half justification hidden in some obscure meaning.

I can do it without looking up anything! Magic is a force in the air and in nature and the uni- in unicorn means they unify it into themselves as a vessel for its manifestation and use.