The most important ingredient in the archetypal "wise old man" is "old." The older one gets, the more likely he is to be dismissed by those much younger as being out of touch, or worse, a has-been, or worse yet, a never-was. A little known quote from the "wise old man" which should be emblazoned on the back of every college diploma would be helpful in the education of the younger generation: those who despite any real experience see themselves as "special."
Here's the quote:
One of the pleasant surprises on growing old is the realization of how little you knew back when you thought you knew everything.