I think part of the discussion missing here, is the assumptions of current, historical, and future exchange rate of bitcoin and usd(or what ever fiat)

you see if price goes up to 1 btc = 300usd, that is a different situation then if 1 btc goes down to 50 .....

I would think in the long term the suck-fixed cost of aquireing bit coin will pale in compareision to the exchange rate change, . be it up or down.