I'd bet that a lot of them probably can. Now, we have more teams, which means more pitchers, which means a more diluted talent pool. Guys like Wayne Franklin would have never sniffed the major leagues in the 60s and 70s. Livan Hernandez might be able to go 150 pitches every 3-4 days with no problem, but the other guys in the rotation can't. So, we have to account for the other, crappier pitchers and give them proper rest.