As for the 1 year wonder, it's a possibility, but it's far more likely that Rodgers will go on as a great QB and if he digresses, he'll still be a very viable option. Cassell would be a guy that I would be afraid of becoming a bust, Rodgers, not so much.
And what I meant by having Rodgers for 10 years. How many QBs franchise QBs have you seen that switch teams throughout his career? Cutler is an abnormality, but franchise QBs stay with their teams for their entire career, or at least the biggest portion, untill they get traded/released when they're on the decline. I don't think that you could find 5 franchise QBs who just left their teams to go and play in another place throughout the history of the entire NFL. And I don't mean Namath, Montana or Favre-like trades.