Honestly, I can make PC's, for family and friends and get 80% of my money.  I like having the extra boards, I bought good chips knowing I would resell them later.  I did not just get something adequate for the job at hand.

I can fold my setup right now for close to 95% of my cost,  if these cards tumble in value, they only represent 80% of the hardware investment, so if they half, I still am looking at 60% and that is the worst possible outcome I can think of.  


As for the grid miner, I am fairly sure no one I know will need one once its of no value to me.