They aren't a pool - they are a single organization that physically controls a huge percentage of the network hashing power, at least until a few of their competitors come online.
What if A and B are not mining pools but single miners?
The Bitcoin network is faster than the top 500 supercomputers in the whole world combined.
http://www.forbes.com/sites/reuvencohen/2013/11/28/global-bitcoin-computing-power-now-256-times-faster-than-top-500-supercomputers-combined/
It is becoming clear that you have absolutely no idea how much independent/distributed processing power exists.
Does this mean I proved you wrong?
