I'm not sure of the technical details of how they are doing it, but I believe the difficulty of mining a bitcoin is proportional to the speed with which they ar

I'm not sure of the technical details of how they are doing it, but I believe the difficulty of mining a bitcoin is proportional to the speed with which they are being mined (and thus the amount of mining going on). So throwing a lot of resources at it just makes it that much more difficult to mine, and would seem not to be productive. (edit: well, at least not based on their current value)