I think it's important to note the teams each coach had as well. Coughlin, for example, never had a team that was considered a Super Bowl favorite. Neither did Payton, in my opinion.
There are variables here, but for me anything less than an AFC Championship appearance is a failure. The Bills have a top 3 QB and damn good team as a whole. They need to produce.
That's the other thing. A lot of us are expecting a Super Bowl now, but it may come when we're not expecting it, like Coughlin's Giants.
The NFL isn't linear.