He lost his outsiderish up-and-coming edge. His condescension stopped reaching up and started hammering down. Instead of telling us that our betters are full of crap, he told us that his lessors were unworthy. And, at some point he reached a stage of inness where he felt comfortable enough to wallow in his sense of accomplishment and to develop a sense of entitlement.
I don't remember ever being a Milbank fan, but there was a time when his mild irreverence was aimed upwards. If your irreverence is aimed at the riffraff, you're doing it wrong.