Montana was injury prone, Brady is tough as nails..So Elway didnt play 16 years? Marino didnt play 17 years? Warren Moon and Doug Flutie didnt play forever?? Bradshaw played 14 years..As did Dan Fouts..Even Montana played 15 years, though he missed a lot of games along the way..That graph is meaningless, as is comparing past QB numbers to any QB from a different era. QB's play a lot longer now than they did back then, in the near future playing well into your 40's is going to be commonplace, we're already seeing it with Brady and soon will with Brees. Wouldn't surprise if in 100 years QB's can play into their 50's, sport is advancing so quickly. So comparing those kind of numbers to present day QB's is silly.