If we wanted to really go off on a tangent, let's ask how many TD's Johnny U, or Bart Starr, or Fran T, or guys like that would have thrown with the rules of today. Back then, a CB or Safety could mug a receiver all the way down the field. Offensive linemen were not allowed to use their hands at ALL to block. So on and so forth. Almost every rule change has been designed in order to create more offense. It's staggering to think what kind of numbers some old hall of famers would put up in the league nowadays, compared to what they actually did.