The Niners (and Purdy) are a totally different team with McCaffery. Mason is a very good runner but he isn't much of a threat in the passing game. They were missing their top 3 WRs and a HOF caliber running back yesterday. Maybe the Packers 4th and 5th string guys are better but If Love was missing Reed, Watson, Doubs and Jacobs he'd probably have a tough go of things.
Their offense, though, is built on play action and one elite thing KC has is an elite run defense.