10. Skilled writers to varying degrees, like musicians, are hard wired with a brain that facilitates their craft. Nurture (learning) is very important to manifest the talent and hone it but the nature variable makes it all possible. No amount of training alone will make any person with normal intelligence a world class musician, song writer, author or mathematician, etc., without some "givens" meaning nature.
Sorry to drag out my psychology background but I do believe that sans the nature variable we can learn to write but will never be brilliant or whatever "skilled" means. Writing for me is somewhat akin to passing a kidney stone.

I do it but it is hard and the ability to conjure up great imagery and commit it to words is very limited. Like a blind hog who if she roots around long enough will find an acorn I occasionally manage to write a decent song. But when I read lyrics of the best here and around the net I am hugely humbled.