Three Super Bowl wins in four years. No one else has done that. So, yes, they have to be considered a dynasty from 2001-2004.
However, since then the Pats* have had more than their share of playoff failures. The best night I ever saw on this board was five years ago, and we all know what that was.
Tom Brady is 36, Belichick is 60 and will be 61 before the season starts. I think the long, slow decline of the New England Patriots began tonight.