Please stop being worried about an single entity having 50%+ of the network,
Someone could have 90% hashrate and as long as he doesn't mess with the chain rules you've nothing to worry about.
I hope AM forks the blockchain and proportionally transfers all BTC to their shareholders.
Then Bitcoin shall be known henceforth as FriedCoin.

Then the devs would change the algorithm to exclude the ASICMINER devices and continue from the fork before they did that ...
i.e. no it wont happen.