There are a lot of reasons why the NL has been getting its butt handed to it by the AL in recent years. Money is one, the DH is another. Matt Klaassan of FanGraphs has another theory: better GMs in the AL than in the NL.
He doesn’t rank them, really. He simply creates two pools: one with the five best general managers, generally speaking, and one with the five worst. By his estimation four of the five best are in the AL and four of the five worst are in the NL. We can quibble with his pool — even with the financial advantage I don’t think Beane is necessarily a better general manager than Brian Cashman, for example — but no matter how you shuffle the names around, I’m not sure you can break the 4-1 advantage the AL has over the NL. Maybe you could still substitute John Mozeliak for Beane, but at this point I’m stretching.
I’m the sort of person who is highly skeptical of silver bullet explanations. Most things in life are a function of many complicated factors interacting. When we add in stuff like the GM gap to the money thing and the DH I think we get closer to the truth than simply blaming the Yankees-Red Sox arms race, for example.