Every team's fans cheer the team and follow closer when they're good. They do it less so when they're bad, but still follow the team. The obnoxious and toxic fan groups still insist they're good, if not the best, when they're mediocre or worse. On top of that, they bad mouth better teams and downplay the opponents success even while their team struggles.
Under that definition I don't think Pats fans qualify (Disclaimer: I am one, though it's my second team). The fans support them still, but they're waiting for the new coaches to show something as the team develops. Sure, the fans were full of themselves for 20 years...but the team kind of earned that, didn't they?
Now, a side story. It was 1987 and Notre Dame had just lost their second game of the season to Penn St., after earlier losing to Pitt. I was sitting in a bar with a fellow resident, a die hard ND fan, having a beer and getting set to watch the Miami game that year. He literally spent 30 minutes going through all manner of intellectual gymnastics on how ND could still win the national championship. I could not convince him that they were done, that the PSU game had sunk their chances no matter what, and if there was any infinitessimally small chance it would be over after playing #2 Miami. He wouldn't hear it. Nope, ND could still win it all!
Miami won 24-0. So, yeah, I'll go with Notre Dame, and the Philly Eagles fans.