Go to the message boards for those teams, I bet they also have people who whine nonstop about one position or another. New England and NYG have also had multiple GMs over that period, I'd say a lot of their success has to do with coaching. New England's old GM went to KC and didn't produce much. Indy's success largely comes from one draft pick that turned out very very well, obviously. But again, if you're the kind of person who needs to be extremely negative and calling for someone's head at all times(Philly fan syndrome?), and the coach is too new to blame, and the QB is new and has done everything you could ask a rookie to do, the next guy in line has to be the GM. If they fired Hurney and the team went 7-9, you'd have to start blaming the coordinators. Or the equipment manager.
I'm not on this message board because I am a ring chaser. Obviously. Expecting a Super Bowl every year would be unrealistic, I get my share of thrills from the Panthers, but that doesn't mean I can't see any flaws with them.