Interesting article, I definitely agree there’s no need to feel like anyone has missed out yet. However, I think there’s a small problem here with the specific calculations done here.
Assuming that 5% of the value of the global economy is connected to the blockchain is not the same as saying that the combined value of all cryptocurrencies will be equal to 5% of the the global GDP. Right now, the entirety of the US economy is valued and transacted in USD but the total value of all US dollars is less than $1.5 trillion (for an economy of about $18 trillion). This is because of “derivative money” and the fact that not every unit of value needs a readily accessible unit of transfer.
So if we assume everything else is the same, the value of all cryptocurrencies by 2020 would be about $380 billion, only 3x what it is today. To actually solve this problem accurately, we’d have to make some pretty difficult assumptions about the future of fractional reserve banking and the velocity of money.