Yes, wins are a team thing, but in fairness, the QB has more opportunity to influence wins/lossess than any other player.
And, like it or not, HOF voters do tend to give some weight to postseason.
I understand your argument about Marino, but he did go to the playoffs 10 times and got to the Super Bowl once, plus at the time he retired, and at the time he retired, and still at the time he was elected to the HOF, he had the most passing yards of any QB in NFL history. Again, like it or not, that's a stat fans, media and HOF voters pay attention to.