I tend to disagree with the assessment that the an artists technique has anything to do with how good an artist is.
Case in point: in Picasso's formative years, he was a great realistic painter. He became a great artist because he pushed the boundary of abstract art that is arguably easier to paint than his earlier work.
To me, Picasso was so good because he built a story (myth) around his work that resonated with so many people.
The Mona Lisa is the most famous painting because of the myth around it. It's a beautiful portait, but is it really the best portrait ever? I think in the same wing of the Louvre there are better paintings of Da Vinci on show, even though there is no crowd around it.
Recently, the myth builders have been (maybe they still are) Jeff Koons and Damien Hirst, I think that's what makes them great artists.