Re: Back in the day...
Good points in this thread. It's just a different environment. For one reason or another, it takes more pitches to get through a game today. (Of course, the pitcher controls some of that; it never took Greg Maddux more than 100-110 to go nine on his good days.)
It's also true that in the really-old days, teams could get pitchers from all over the place; the minors weren't tightly controlled by MLB clubs, there were more minor-league teams, there was no draft, and the money wasn't big. A team could afford to practice Darwinism with its pitchers because there were more where they came from. Not so today.
Finally, the rise in status of relievers has something to do with it. In many cases, it's not that a starter couldn't go a little deeper into the game, it's that the manager chooses to pull him because he has a good bullpen.
I think there's something to the notion of throwing more being good. Mazzone's always been big on throwing twice between starts. One of the BP guys, in an article wishing for the return of the four-man rotation, said it's not pitching that causes injuries, it's pitching while fatigued.
Not all who wander are lost