They deserve credit, but the path to the superbowl is far easier in the NFC than in the AFC. It's just a fact. All the elite QBs are in the AFC. Kansas City, the best team in the NFL for years now, is in the AFC.
So yeah, they have done more, but there is a reason for that and it isn't just because they are better than the Bills. Opponents and competition are a huge part of that.