Look back, even 20 years ago. You've always had freakish athletes who could play 9,000 innings in a row and not have any problems. You could have guys go on 3 days rest for a month and not have problems.... but the number of guys who blew their arms out, who suffered major injuries, or who had a "dead arm" after 3 or 4 years was much higher than today... and the number of 34 year old guys who can play like that is even fewer. The great ones did it, and that's what made them great. You never hear about the ones who didn't. Like, say, Cal Eldred, who was overworked and overused his first three years in the league and was never close to the same pitcher afterwards.