Also, there is something called an aquired artistic abilities or a forced artistry. In this one has to be good at it because he has no other choice, as in the case of potter. He inherits the business, He's forced into it . He does it for a living.But with time he improves, his imaginations improve , and so improves the art. Here the art is for a life sake which has some artistic quotient attached to it as well.
All in all, in today's world, 'art for life' and 'art for art' are complementary to each other. One has to survive depending on some growth of the other as well. Every commercial artist may not be that good at art and those who are may starve for its value. So a balanced equation of a bit of both,makes a complete artist.