The less than 4BTC you earn with the hardware will never be worth as much as the 4BTC spent for the hardware, no matter what the price of BTC is...
This seems really, really hard for people to understand.
This is solely what I calculate ASIC hardware on , since most hardware is sold @ BTC prices. It doesnt matter its USD conversion and I leave power cost out of it too cuz that involves USD conversion.
So yeah, everything announced and / or selling right now will most likely never achieve this - or so it seems.
But, I suspect that difficulty will achieve some sort of flatline around 1.xxx billion and hold for a while. Giving room for some of these devices to make positive ROI. Theres just simply not enough hardware announced to achieve the 328 PH/s hashrate required for a difficulty of predicted 42billion.
At most there is 10PH or so in the pipeline.... and that puts us around a 1.3billion diff...