It's not just as simple as that. Many people are speculating that BTC will increase in value as it continues to become more popular. For .893 BTC they can get a device that should get 10% "interest" in a several months and still have intrinsic value to them or someone else (to sell). They DO NOT think in fiat. They don't have to sell BTC to pay their electric bill, nor would they, because they believe it will turn into the million dollar pizza deal again at some point. Why did you pay BTC for electricity when you could buy a car with that much BTC today (5-10 years later, for example)? At any rate, that 10% "interest" on a BTC investment even before a hardware resale is better than putting cash or even BTC in a bank at 0.4% or 0% interest, which is below the point of inflation.

By making this statement, BA demonstrates that they don't understand the mindset of speculators, which includes their customers. It doesn't matter if you or I agree with this 100% or not. The fact remains that many people mining believe it, and mining won't stop unless and until the value of Bitcoin drops back to near nothing with no hopes of ever recovering.