I agree that it is an extreme example and it is why I made it. The Patriots did just fine without Brady for 4 games, I don't think the Packers would fare as well. Again, losing Rodgers and using that as an "excuse" would make me ask, "Why weren't the Packers prepared for something that was totally feasible to happen?" This isn't expecting his replacement to come in and equal his numbers, but it is expecting a team to be able to still find ways to win after the loss of 1 player, even Aaron Rodgers.
Losing Rodgers and the rest of the team not being able to win without him, might be a reason for losing, but not a valid excuse for losing IMO. There is a difference between a reason (loss of AR) and an excuse (not being prepared).
But you are right in the sense that the Packers have pretty much pinned their success on one guy, Aaron Rodgers.
No excuse for that.