That is why the analogy of stealing does not work. With a thief, we want to know how much money he stole, and from whom. With the artist it is not how much he took and from whom, but what he did with it.
Why do we pigeonhole and label an artist? It is a sure way of missing the important, the contradictory, the things that make him or her unique.
Most people think an artist tries to be original, but originality is the last thing that develops in the artist.
I strongly suggest that we play down basics like who influenced whom, and instead study the way the influence is transformed, in other words: how the artist made it his own.
Most artists have experienced the creative block. We get stuck in our work. We beat our head against the wall: nothing. Sometimes, it is because we are trying something at the wrong time.