I just don't think that is the case. X raced out to a big lead and then proceeded to play like CYO 4th Graders as they blew it. It was eerily similar to the UC debacle. I don't think the "big head syndrome" had much to do with it. If you watched the game you clearly saw how frustrated the Musketeers were and how they were painfully aware they couldn't hit the broad side of a barn. They kept scrapping but looked exhausted and dejected.
Edit: I do think the swollen head syndrome is a real problem on occasion. I just don't think it was the issue last night, nor do I think there was any true "regression to the mean." It was a bad night, simple as that.