The author's usage of "meta" doesn't match up with how I've seen it used elsewhere. He refers to the "metagame" when really he's just talking about the game itself.
If there's a really popular rush deck, do you drop some cards which shut down blue control and put in some anti rush cards? That will help when you match against the rush deck, but if everyone does it, then when you reach the finals you might be against the control deck.
That's the metagame, at least how it's used in those circles.