It was some game!
Someone suggested that covered stadiums favor the offense. That makes sense to me. Removing random elements like gusts of wind, looking into the sun, etc. should allow an offense to hone their game. Covered stadiums are more common now than in the past and this may throw off historical comparisons between quarterbacks.
The Cards could have opened the roof. The weather was beautiful. They decided they wanted more noise to help them.
I guess it did.