Z, the point of the ROI comments is to show that Bitminer has an unworkable pricing schedule, and to try to convince them that it is in their best interests to modify it. So, since they aren't looking in the speculation threads, and since Giorgio is deliberately ignoring that the advance and retreat of BTC to USD conversions does not affect our estimates at all, much less invalidate them, I thought that this was the place to change his mind... it didn't work. Oh, well.

His ignoring the numbers doesn't really affect the numbers: he prices his chips in BTC, regardless of the exchange rate. So, we can calculate the expected return for any given difficulty, in BTC, and compare it to the cost of the chips. The numbers say that for every BTC spent on a chip that is sold at 0.85BTC, and put into operation in January, it will return only about 0.3BTC over its entire lifetime - ignoring the cost of the boards, power supply, and power.
Edit: According to Mining Dashboard, assuming current difficulty increases continue without the rate increasing, the lifetime return for 1BTC is 0.33 BTC (0.6617 loss), regardless of whether you price the BTC at $100 or at $200. No shipping, no power, no boards, no case... only chip costs considered. Check for yourself.

Like I said - a very expensive hobby, and Bitminer is making things that can't be considered anything but toys for rich men.

I thank you heartily - you have been extremely polite in your responses, and I appreciate the civil discussion. Since I can't, evidently, be convincing, I won't push the point any further.