A number of years ago I heard an anomymous official from Sotheby's interviewed on NPR. This subject came up and he answered it like this. He said that most newly successful artists were young people who looked upon the rich old men who bought their works with derision. He felt that they did this sort of thing because they could get away with it; because there's enough of a mindless stock market aspect to the art world that it can turn huge profits. In closing, he thought that most of them outgrew it.