There are a few issues with this statement. When every faction has a "broken" combo, then no faction is "OP". This also means that it's not a rock-paper-scissors meta so much as it's a paper-paper-paper meta. This leads to some deck including a bit of rock and/or scissors, but, mostly, it remains paper at it's core. The point remains, you don't have to prevent the opponent's combo, if yours is even stronger. Timing also matters a lot. The best example are Dwarfs. When you can start the second round with quadruple Mercs, then you are ahead in play. However, if you start 2nd, the opponent can put down his own engines, which may spiral out of control.