I believe I see the point you're trying to make. You could say the same thing by stating "Dan Marino needed to be better than Bob Griese in order to win the superbowl.". Kelly was a great QB but did not win the big game. If I remember correctly, a lot of Bills' player's performances came up short during the superbowl (see Bruce Smith, i.e.) If Kelly had such a great supporting cast and they win and lose as a team, then maybe the Bills as a team and the strength of their superbowl opponent had just as much to do with being 0-4 as Kelly's performance.
I say that the Bills, not just Edwards, need to be better than those teams of the '90s.