I don't understand this. As difficulty rises, your device is going to be progressively less efficient at mining. Even if the returns are near the cost of the electricity, it doesn't seem that will last long pat the ship date, especially if 21 is taking a cut.

I can only assume that with Cisco and Larry Summers involved, someone has done some compelling math.

Perhaps the fact that BTC deflates compensates for the loss somewhat as more devices are brought online?