There are more factors than the 1 you pointed out.
When it comes to the defense having a positive impact on the game, both Griffin and Wilson benefit. Luck does not. Using Pro Football Reference's "expected points" metric, the Seahawks clock in with an impressive +40.04 rating. The Redskins are a less impressive -65.20.
The Colts: -97.63
Before Luck even gets the ball in his hands, he has to contend with the errors of his own defense, which gives up a ton of yards, can't get teams off the field on third down, and can't pressure the opposing team's QB. They have just 28 sacks.