They aren't wasted because you get Bitcoins for them.
Nope, that's just a neat way of distributing the currency.
It's neat, but not efficient. A miner is left on as long as the bitcoins it produces are worth more than the power cost of producing them. In other words, in a (plausible) worst-case scenario, each bitcoin mined will cost just a fraction below the power burned to mine it. If the FED was working on that kind of margin, people might be even moar pissed
