My theory is, once the blood starts flowing in the streets come January or February, and the common miner comes to the realization they will not hit ROI, they will stop buying new hardware. Then, and only then would be the appropriate time to buy. Once the "overeager" money is wiped out.
Thoughts?
Agreed. I cannot think of the current situation in words different than a bubble. However, what happens is that people waiting for asic *will* put them to work. So considering the current level of demand, the difficulty will continue to jump for a while.
I have improved my estimation using the current next difficulty estimate (78% increase, not 100%). The price to reasonably pay for a miner is in mBTC. This price involves one month delivery security (yes - optimistic) and one month insurance against huge difficulty increase
https://dl.dropboxusercontent.com/u/4813922/mining%20profitability.png