It could be that the Rams exposed what good coaching has covered up all year: that the the Bills defensive personnel just isn't very good. Rapp, Rousseau, Bernard, and Benford are excellent, but the others are average or mediocre (Milano could improve dramatically). In other words, Babich might not be the culprit; in fact, he might be the only thing holding the defense together.
I'm not defending McDermott, though. When the team needs him most, he lets them down. If they win it all, it will be despite his game management, not because of it.