People like to overthink things alot of times. Do it myself from time to time. Not saying I liked the Packers, but nothing on the field over the last 3-4 weeks would point to taking the Raiders. Yet, all I heard all week was "this could be the week the Packers lose". People like to buy into that shit like UFO sightings and the next thing you know people are surprised when the Packers go up 30.
Also, not sure how easy it is to have a letdown when you're 12-0 and on the verge of making history.