A: (Salome) Well, people do learn to write that well. I mean, every writer who has been published has learned to write well enough. Maybe only Harlan Ellison got his first attempt at a novel published on his first try. (I don't actually know if that's true. It might have been William Gibson.)
But is there something innate about the ability to write well? Yes. Just like some people are good at math, some people have facility with language. That's a definite bonus. Some people seems to easily access their creativity. Also a bonus. Some people are able to generate sequential ideas logically. This can be very helpful.
I do think that not everyone can learn to write that well. But people can and do. It takes a lot of work. Just sitting down and putting the right number of words on the page and roughly simulating a novel is unlikely to produce the desired result. It's like saying, I want to be a ballerina, putting on the costume and turning on the music. Will you instantly be a ballerina when you hop around in time to it? Will you be one if you imitate the dancing you've seen at the ballet? Clearly not. But it's the first step. With dedication and learning, you'll get closer. Actually F. Scott Fitzgerald's wife became a ballerina as an adult, though she was warned that it was impossible. So yes, it can be learned, with more or less difficulty, depending on your natural abilities, your commitment, and your willingness to learn technique.
A: (Tim) Yes, writing is a skill that can be learned. Some people have an innate facility, of course. But that's not the only way. The more inherent talent you have, the easier it is to improve, but it is possible to get better. Like every other skill, it requires dedication, study and practice to become good. Going from good to great is harder, and requires talent as well, but fortunately for the vast bulk of us mortals, truly great writers are extremely rare. There are things that make good writing less trying. Reading voraciously. Having a mind that makes lateral jumps. Self-discipline. Bravery. A good memory. But plenty of writers have made it into print with the Big 6 with nothing more than a whole heap of hard work and determination.
It's important to remember that there are no guarantees, and if you're after a Magic Pot of Gold, the odds of a lottery win aren't much worse. There's a lot of genuinely good writers who don't get published. Mostly, that's for reasons internal to them, but you never know how you'll do until you step up to that plate, and luck plays a savage part as well. So ask yourself why you want to be a good writer. If it's for fame, sex and/or money, well... Heh. There are far quicker, more reliable ways.
Writing is an incredible activity. It's nourishment for the soul, your own little portal into true wonder. You don't need a Big 6 book deal for that. Just pick up your keyboard and write. But if you need to be good, because the fire in your mind will accept nothing less, and you're prepared to drive yourself relentlessly... then yes, you can do it.