I don't think it makes sense to compare Manning's stats to those of guys like Kelly who played in different eras, where QBs did not routinely rack up 4000 and 5000 yard seasons. Manning had amazing defenses in the years they won it all, so not sure about the supporting casts being that different. He has definitely been more durable, which is interesting, because I almost feel like people would give him more credit if he'd retired a couple years ago.