Because the 49ers are a consistently great team in spite of their QB. Their QB isn’t the reason they are a top tier team, unlike the Chiefs or Bengals, who are largely great because of their QB.
Every year, the 49ers succeed based off of their run game, defense, and great coaching. Those remain in tact despite Jimmy G’s injury. That’s why they are so great and ranked above us, and until we are a capable of beating them and getting to a championship/Super Bowl in this decade, it will remain that way (and deservedly so.)