Wow. You must live in the vacuum that is Boston. Newsflash - fanbases in every area are crazy about their teams. Even in Miami the last five years, the Fins, Marlins, and Heat are all very, very hot topics with tremendous fan bases despite the fact that the Heat are the only team in those last five years to bring home a championship.
Besides, attendance at Foxboro was WAY down before the 2001 season. We do have rabid fan bases with the Pats and the Sox but, let's face it, Foxboro wasn't exactly "jam packed" before 2001.
Oh, and to be fair, Philly's fanbase is a lot more rabid than Boston's.