I don't think they WANT to lower the barreling proofs (I'm talking about the suits, not the distillers). The higher they can put in into the barrel, the higher it is at dumping, and the more water they need to add to get it to bottle proof. The more water they add, the more money they make.
And THAT'S what's driving barreling proofs up and bottle proofs down, not anything practical about the whiskey-making process.
It's about money. Much of distilling (
to Heaven Hill and Buffalo Trace) has become corporatized.