Assuming a fairly low difficulty increase of 80%/month a block eruptor would make like $17 if it started mining today. Best prices on ebay are around $50. Well, assuming BTC hits like 3.5k it will break even. In which case it would have been better just buying bitcoins ...
You could have bulk purchased a while ago for less than that. Also if you use that logic (which is beyond any common sense), buying bitcoin is always better than buying mining equipment.