By 2020 btc holders will be filthy rich 
2020 is just 4 years away. If the price double every year, it is just 16 times of present value, or $7000 each.
That is not possible at all, we may see maximum price of $700 by the end of this year and if user adoption goes higher in future then price will be around $2k in 2020.
I've read it before today, but it seems to me people are dreaming out aloud. An asset doubling every year, based on what? This is not going to happen, and it's not the goal of bitcoin.
Rather then to hope/dream, invest in your time in 'important' things.