I think that art is a combination of both natural ability and learned technique. A natural artist can be limited by lack of knowledge. Having knowledge but no natural ability also is not going to lead to success.
I agree with this.
I also think that many artistic techniques can be learned, though I am not sure that everyone can learn them. I do not have any apparent natural ability to draw, but when I took an art class I was able to learn enough about technique to produce decent work. Of course, as soon as I stopped using those skills, I lost most of them.