Of course it is fact. But you are using facts to spin the conversation in another direction as to avoid saying JC was correct. And if you are referring to Manning as that "one man that barely won one", I most certainly do not credit him for being the best quarterback in the last 15 years. That honor belongs to Brady.
So, provided I looked everything up correctly, of the Super Bowls you mentioned (Steelers (X2) and Giants), Super Bowl XL is the only game where the winning team relied more on the running game than on the passing game. In yardage and in scoring. Otherwise the other two Super Bowls were pass heavy in yardage and scoring, and that includes the losing team.