I agree that the most important component to success is steady, well-executed practice and lots of it. However, those lucky people with abundant talent progress at a much faster rate and end up with a vastly superior result, given equal amounts of hard work. There are many facets of talent, too, and some people have some, but not all! There are very few folks who have all the prerequisites to arrive at the pinnacle of artistic achievement. Not only do they need enormous self-discipline and creativity, but they must have taste, knowledge of style, an inner sense of rhythm, strong and nimble hands, a quick mind, calmness under pressure, etc., etc., etc. But no matter how many of these attributes musicians may have, they still must do the hours of practice, just not as many as those not similarly endowed. My conclusion: lack of natural talent is relevant, because a career in music is just too much work for a non-gifted person, and they are competing with those who can play the same or better with much less effort.