Regarding the oddity of six 300-game winners starting their careers in the '60s, but none in either the '70s or '50s, Mike wondered:
Well, why? I can see that the use of 5-man rotations may have started to effect pitchers who started in the ''70s and 80s. But why none in the Fifties? And why are there six who started in the Sixties? Does the dearth of hitting have anything to do with it.
[Neyer] points to the Hall-of-Famers debuting in the '60s getting a decision in a slightly higher percentage of their games. To this he adds, "Over the course of a long career, the difference might cost a pitcher ... approximately 10 wins ... but that's not usually going to make the difference between winning 300 games and not winning 300 games." So what does? Neyer points to five-man rotations for the current and future classes and never again addresses the earlier non-300-winner eras.
I am intrigued. I have a feeling that pitcher-friendly eras breed young pitchers who have the ability to win a good number of games over their careers. That would mean that there would be fewer 300-game winners in the heavy hitting Thirties, for example. I do not know if this is true. I envision studying the effect of hitting (batting average, on-base percentage, and slugging percentage) for each era and its effects on the ability for a young pitcher to amass a large number of wins over the span of his career. This may be a fun activity to perform during the strike, like when your mom reserved some activities for rainy days when you were a kid. I'll keep you posted.
Well, sorry to steal your thunder, Mike, but I think the explanation is just as Rob Neyer said it was: a statistical fluke. I looked at all the 300- and 250- game winners to start their careers in the 20th century (I ignored the 19th century, because, well, it's weird), and charted them by the decades in which their careers started. I got the following:
_______Number of Wins
Remember Sesame Street? "One of these things is not like the other..." With the exception of the first decade of the century, there was no other decade with more than one 300 game winner, and there were none with even more than three 250+ game winners. (Actually, Early Wynn is the lone 300 game winner from the 30's though he only pitched 20.3 innings in 3 games in September of 1939. He went 0-2.) Roger Clemens and perhaps Greg Maddux are likely to bump themselves up into the 300 win category in the next few years, while Tom Glavine and maybe Randy Johnson could join the fold of 250 game winners very soon.
All of this mostly suffices to tell us what we already know: It's really hard to win 300 games in the major leagues! That's why only 20 people have ever done it, and only 12 whose careers started in this century. But the point that Neyer made stands, in that we do have, if not a bounty of great pitchers, at least more than our fair share of greatness to watch. Enjoy it.