^^^^^^^^^^^
I think that thinking like this really misses the point.
IMO, you ask questions like:
"If Deacon Jones had the diet, exercise, and medical expertise that players nowadays have and played during the time of Bruce Smith, would he have been as good as Bruce Smith?"
or
"If Bruce Smith played back then when diet, exercise, and medical expertise were relatively undeveloped, would he have been as good as Deacon Jones?"
My theory is for the most part, the greats back then would be just as great today because they had the talent, intelligence, and work ethic to be great in their era. IMO there's no reason to believe that they would be worse in a modern context.
If Babe Ruth was cloned and brought into the world on the same day that Barry Bonds or Mark McGwire was and was encouraged to play baseball, I would still fully expect Ruth clone to be one of the greatest players in baseball.