I don't understand what you're talking about. If everyone switched off half their equipment, they would all still make the same amount of money, 25BTC per block, and the difficulty would be 1/2 what it is now. The problem is there would be no way to coordinate everything. A miner who cheats would get 2x as many blocks.

The block reward is going to drop to 12.5, and then 6.75, then 3.375, etc over time anyway. It's already dropped from 50 to 25.