Just a couple hours ago I wrote a post asserting that writers are made, not born. Of course, there are two sides to every story and the 'nature vs. nurture' debate will never truly be settled.
Perhaps, writing ability, like the ability to run a four-minute-mile is somewhat in-born. Maybe if your mother listened to Mozart or Beethoven while you were in utero, maybe if you were exposed to books early, if your parents' were well-read and well-spoken, you have some natural advantages.
Like most things, it's probably a little bit of a combo platter.
You need the genes and you need the gusto.
One thing I will tell you, is that good writers often train themselves in the process to speak articulately and argue persuasively.
Just now I overheard two people talking about the state of our planet.
"What's happening in Venezuela is cray cray," won't cut it.
Nor will the response "Totes McGoats."
Not sure about the spelling of that last one.