Yeah, I still don't believe any of this.
First of all, 8 of Buxton's 33 hits came on infield grounders? Doubtful.
Second of all, he's not turning into Matt LeCroy. He will be an exceptionally fast runner into his late 30s at least. Not as fast, sure, but still very fast.
He's not losing 50 points of OPS over infield grounders.