The 49ers were able to run a very conservative offense because of their dominating defense.
KC doesn't even come close to having the defense that SF has. And Andy Reid does not run a conservative power run game.
This is not going to be the same Alex Smith you saw the last couple of years. Compare his performance the last two years compared to pre-Harbaugh when the defense was not elite. Why do you think it was so easy for Harbaugh to plug and play Kaepernick in for Smith? The defense carried those teams and the offense was a real conservative one that doesn't require a great QB to run.
Alex Smith has (barely) broken 3000 yards just once in his career and has thrown for 300 yards just twice. Is this a quarterback that can carry a bad team to the playoffs?