Eventually, technological advances will lower the cost of resources required to mine Bitcoins. You are not addressing that with your math. I will post more detailed calculations later.
i will wait for your post about calculations.
i think its not happen when bitcoin halving come,i guess some miners quit from mine bitcoins or at least they think mine bitcoin no longer profitable. lets wish this is really happen.
The value of Bitcoin is not even rising that fast and you have to know that it is really hard to predict what will happen in the future with Bitcoin in 2020 so that is risky.
And many people are thinking that the value will be higher in that year because it was already stable for a long time.