How Much Do We Need Billionaires?

Mark Thoma, posted this article by Brad DeLong in which he attempted to answer questions regarding our dependence upon billionaires.  He wrote it before the financial crisis which has brought this question again to the fore, but DeLong's essay on the subject provides a good history lesson for all of us.  Especially for those who are too young to have been part of our recent history.  We can all benefit from his history lesson and we can learn by debating the questions that he has raised.