Specialization is for people who want to become very good at something. Life's too short for most people to become competent at a wide range of activities while still becoming good enough at one thing to change the world. Grigori Perleman and Warren Buffett are not generalists.
Up voted to correct the idiotic down votes. HN recently seems to have become plagued with people who think the down vote is to be used when they disagree with someone.