1. TvT is one of the favourite matchups in SC2. PvP nad ZvZ are hated, but it's due to how these factions are designed. I can imagine USvUS in vcoh as potentially interesting match-up, but what about Brits v Brits?
2. BS. I can imagine a lot of people who'd buy a game because of mirror matches, try the competitive scene and increase the competitive community. I imagine they're all called Fred.
3. Your math is bad and you should feel bad. There are 3 possible matchups in 1v1. I can imagine a lot of things for the sake of argument. In fact, I can imagine that you're wrong, and I'm right. Does that make it a fact?