In order to be viable 2.5 years from now, AM would basically have to give the chip away. 14nm will be readily available by then and most manufacturers will have produced far more efficient chips. 2.5 years is far too long a life for gen 3.
No one knows what BTC/USD exchange rate or difficulty is going to do over the next 2 years. If there is a crash or stall, then yes, 2.5 years could very well be the life expectancy of gen3. Do I think that is likely? No. But it is an upper bound. 9 months is my lower bound, which I think is also unlikely. But it is still reasonable to think in min/max caps when doing projections.
Who cares about nm size? Do you buy the camera with the highest MB pixel count, or do you get the one with a good aperture and optics that produces the best photo quality? Based on the specs AM is about to release chips that are over 2x efficient as their competitors 20nm chips. If competitors want to spend a boat load of money to do 14nm nodes, then I say they can knock themselves out.
If you think that's clear, then tell me when gen 4 chips will be released, based on that information. All that that paragraph say is that AM will try to double the number of transistors every 2 years while making the chip more efficient.
Well I think it is about as clear as it can be. It means they aren't hanging up the towel after gen3. Gen3 isn't even taped out yet but you want a specific date when gen4 is going to be done? Please...