Because you are wrong?! I explained it over 3 posts why.
The engine needs at least 3 turns to work properly. 3 Turns in which the other guy can play: Mongoose, Goyf, Bolt, Predict the top card away. Or something like that (I did that btw. It was very funny). And that only if we act on the assumption that we play: 1st Turn SDT, 2nd Turn Counterbalance.
And Counterbalance still won't prevent the gamewinning cards such as BTS, Force of Will, Vedalken Shackles and Repeal. BTS also makes the Engine suck like hell. Being affixed to play out the Counterbalance engine can give the opponent a double-timewalk, because the timing then is wrong. The thing is that Counterbalance doesn't handle the stuff that's already on the board.
Counterbalance is never INSANELY good in, neither in the earlygame nor in the midgame as a stabilizer. Of course it disrupts the the opponents actions very well, but playing Counterbalance does absolutley no pressure. And pressure is the key to win the mirrormatch, not the Counterbalance Engine.
Or why do you think that NQGr does so well here in Germany? Because it's very strong against Baseruption, and it's wins even against the Counterbalance Engine.
Of course th Engine look insanely strong against the mirrormatch, but practical it's a matter of timing and pressure.