Old QB stats are interesting. You don't even have to go back to the 60's. Roger Staubach only had an over 60% completion percentage one time in 10 years. That year, he only had 286 attempts for 2,428 yards. Terry Bradshaw never cleared 60% completions. These guys were the two best QBs of the 70's. Dan Fouts is the only guy from the 70's whose numbers look remotely modern, but Derek Carr has better numbers than he did. Joe Montana was the first guy to have modern QB stats and he never threw for more than 4,000 yards. Mahomes has never had fewer than 4,000 in a season that he started and has thrown for more than 5,000 twice in his career. Different game, indeed.