We all know that Rex Grossman has been to the Super Bowl, and conventional wisdom says he went on the backs of his defense. We consider it the same as the 2003 Ravens who won the Super Bowl with Trent Dilfer who only started the last half of the season.
Clearly, Baltimore won the Super Bowl in spite of their quarterbacks that year.
Maybe we judge Grossman too harshly. The 2006 Bears were 2nd in the league in scoring that year putting up 427 points. I’m not sure we can say that Chicago made it on defense alone like Baltimore did.