Good teams win games when they play badly. Good teams play 60 minutes. Good teams don't have momentum swings within a game or from game to game (offense is bad week #1, defense is bad week #2, etc.)
The difference between teams with talent and good teams is in the leadership. QB, veteran player, coach all own this.
These Bills are not a good team. They're a team that can't make it happen when they need to, even with a 15 point lead in the middle of the third quarter. Never mind how much fun it is to watch Tyrod or how smooth Sammy looks when running routes. Never mind how complimentary the opposing offensive line is about Kyle or how sharp one or the other of the Browns is at making open field tackles. This is not a good team. The Bills have had very few good teams and none outside of the Kelly era.
Who didn't step up yesterday? Tyrod, Sammy, the Browns, Kyle and the Defensive Genius coaching staff. Who cares if any of them stays? They're not going to lead a good team in Buffalo, not next year and not ever.