Um... no that's not simple math, you are basing your math on the assumption that mining will only depend on block reward, which means mining will stop once block reward is negligible. That's simply false, if mining were to stop once block reward is negligible, then Bitcoin would have failed at that point, due to no network security.
It is expected that transaction fee will make up for block reward, we are already seeing average transaction fee of nearly 1 BTC per block as of now. Transaction fee will go higher as adoption grows.
Also you are not taking into account of blade miners and possibly USB miners that AM is currently selling at insanely high profit margins that will bring large and fast short term cash dividend to investors.
It is expected that transaction fee will make up for block reward, we are already seeing average transaction fee of nearly 1 BTC per block as of now. Transaction fee will go higher as adoption grows.
Also you are not taking into account of blade miners and possibly USB miners that AM is currently selling at insanely high profit margins that will bring large and fast short term cash dividend to investors.
I suggest you re-read what I wrote, my last sentence stated clearly my analysis excluded fees ie block fees and also sales from selling hardware devices ie new ASIC sticks or others.
Both of these are hard to forecast, as is the offsetting future costs of running the ASICs and the business overheads, which were similarly ignored for the purposes of the simple analysis.
