I really don't understand the end-game for miners. When the last Bitcoin is mined, what's to become of the 100 Petahsh of equipment out there? There isn't any way that can be supported by transaction fees. I am sure I don't want to own a 100 Terahash of gear when the last coin is mined, because there is no way it will continue to even pay it's electricity bill. There will have to be massive write-downs in the value of equipment and facilities I would think. This situation will come into much clearer focus after a couple more halvings in block payout.
You're thinking way too short-term. When the block rewards become insignificant, the idea is that Bitcoins have gone up considerably in value (or failed and crashed to zero) and it takes way less coins to pay for the electric bills than it does now. Additionally, the amount of transactions should be way higher, which increases fee earnings.
Since the reward-halvings will go on even when the reward drops below 1 BTC, the transition from miners primarily living off block rewards to miners living off transaction fees will be smooth and if transaction fees don't grow quickly enough in value, difficulty adjustments will make mining easier as less efficient miners quit. There will be no single moment where people will be saying "well, that's the last coin, lets hope the fees are enough now". Eventually there'll be a point where the block reward goes from 1 satoshi to zero, but other than it having symbolic value, noone will care.
