Writing skills: "the ability to express oneself in a written medium"
I think that definition is mostly true. It is also "true" that a whale who exits the ocean of its own accord will often return to the water with a large "splash" and displace water as it does so. To describe this event clearly does not "explain" it. It also does not come close to capturing how magnificent it can be to observe.
Writing is often breathtaking and wonderful. To be skilled at this practice is no more a cultural artifact than oil painting or violin playing. The ability to put a brush in paint and apply can be taught. To transcend that and make the canvas mean something that most of us have never seen before-well that is something else; all together different. The ability to play a violin is a rote skill, a techincal accomplishment. But to play notes that touch your soul, that make your chest heavy and the back of your neck shiver, that is so much more than practiced strokes.
So how do writers do this? I wish I knew.
I don't know how good writers find a way to get past the simple presentation of words and sentences-but they do.
Skilled writers create many things and a definition of their work that is strictly antiseptic is unfair and incomplete.