They have to find really cheap power, if you ask me! i want to see 0.01$/KWh! That way they could build a really big farm an mine the hell out of the blockchain. AM isn't a small player, they should go as far as possible and re-claim those 40% in 2015! Also they could continue to offer a cutting-edge cloud mining!
Even if the network wouldn't grow much from today on, claiming 40% of the network possibly means building 100-150MW worth of
new Bitcoin mines in 2015. That's about half of all of Google's capacity (265MW) by power combined. And twice the size of Facebook (78MW). And it remains a moving target during and after.
I had a post here with some numbers I put together recently:
Energy Consumption of the Bitcoin Network
http://bitcointalk.org/index.php?topic=520977.msg9825138#msg9825138Never going to happen, they simply don't have the cash to do that on this generation. Even Bitfury's level of cash would only just allow them to do that (if they started from 0%).