I don't think I agree, I don't think the goal is .500. You have to have top talent at some position to be considered a contender, and the gap between blue-chip talent and rank-and-fil nfl players is noticeable. You could look at nearly every position and find a game-changing talent, someone who's play every week can change the outcome of the game
Donald, Bosa, McCaffery, Henry, Jefferson, Warner, and Kelce for instance, are not QB's. Obviously, when paired with a blue-chip QB they are far more likely to be contenders, you still need the best talent outside of the QB position