If you (people in general) believe that today's athletes are superior in terms of conditioning, diet, exercise, training, supplemental medicine, then how does that logic compute with the fact that guys like blyleven, gibson, marichal, ryan, etc. threw for more 300 innings during some seasons.
My only thought it has to do with kids today suffering from burnout. Yet, most kids still play ball today as much as kids did, when I was growing up.