The scenarios below are called a "race to the bottom". This is seen in natural resources with a limited supply, e.g. not renewables. Famous races to the bottom include the nOrth Sea crabbing industry, old hard wood logging, coal and petroleum. As the resource bcomes scarcer more people pile in as the price goes higher. The increased rate of extraction of goods increases the rate of depletion and the price rises due to scarcity. This death spiral goes on until the bootom is hit and the entire sector, plus the industry they feed, dies a horrible death throw as they seek bail outs.
Sorry Floridabear, your math is off. At $0.15 kw/h power cost, a Single is still profitable to a worthwhile degree even at 900 million difficulty. It's going to be a bit of time before we see 900 million difficulty, from 19 million now.
You really have to define "a bit of time." I defined it clearly in my post, and my math is not off based on the assumptions I posted. Please don't accuse me of being wrong when I provide all of the assumptions I used for the calculations, unless you've done the math with those assumptions yourself (and you can prove I did them wrong).
My math is correct according to the assumptions I gave and I stand by it. A 50 GH single will only ever produce about 28 BTC ($2800) if delivered in September and my assumptions prove correct.
If you want to argue about 18% increases every retarget being too pessimistic from Sept '13 to March '14 (when all currently available BFL devices become unprofitable at $0.11/KWh) , that's fine, but don't just say "your math is off." However, I don't think 18% is at all unreasonable. When GPUs were rolling out, we saw difficulty go from 19 to 9000 in about 5 months. And that's an order of magnitude greater than the change we're talking about (19M to 900M). If ASICs come on line at that rate, we'll be at
9 billion by February (except that none are profitable there, so it won't happen). But I don't think 900M is unreasonable by Jan 1. Granted we will see some leveling off after that as less efficient ASICs become unprofitable. But if 28 nm products are real and rolling out, they will quickly obsolete everything less efficient. This is a pretty inevitable path we're going down.
My entire point is that delays are
extremely costly going forward. Progress is relentless.