I think Tywin's badassery has people over estimating his ability to play the game. Obviously he is a grand master, but he isn't the only one, and if he's ahead of his peers, it's not by much.

An interesting thing I picked up on when looking back: Baelish is presented to us as essentially being on the same level as Varys, Pycelle, and some other lesser power players-- but in fact, while Varys isn't a chump and Pycelle plays his own special sort of superb game, Baelish moved up above them, and this was signified in his chaos is a ladder speech to Varys. Now he's playing in Tywin and Olenna's league, even though neither of them are likely to realize it.