There is no reason at all to believe this is true. Pitching is better than ever. These are objective facts:
- Pitchers throw harder than ever.
- Pitchers are dominating the game through strikeouts to an extent never before seen, but aren’t walking any more men than they ever have.
- Scoring levels are not high, despite conditions for home runs being extremely favorable.
- Improvements in fielding cannot explain any of this.
The idea that expansion makes pitching worse baffles me; it should make hitting worse too. AAA isn’t a hitter’s paradise, so the notion that the talent level below MLB has a disproportionate amount of capable hitters and incapable pitchers isn’t really supported by common sense. I went and looked at offensive levels in expansion years but it’s hard to tell what happened. Sometimes things did not change to any significant extent (1961, 1962, 1998) and sometimes they went up, but the times they went up there’s either
-
Conflating factors: offense went way up in 1969, but they changed the rule to make that happen, or
-
It just makes no sense. In the 1977 AL and 1993 NL expansions offense went up a lot - but it goes up just as much in the league that DIDN’T expand, and you can’t explain it by saying that league lost good pitchers to the expansion teams. Indeed, in the case of 1977, the Mariners and Blue Jays had probably the most restrictive expansion draft rules ever, and they got pretty much NO good pitchers from any other team. Why would the Seattle Mariners being shitty cause the Phillies to score more runs? Weird.