Another thing that has to be taken in mind is that for Bitcoin or any other crypto to be mass adopted, the use of hardware has to be mass adopted as well. As long there are people without internet, smartphones or even regular phones that can receive sms, fiat will be used. I agree that the next 5 year will be crucial for the development of crypto and the new market it has developed.
Now instead of having "... 164 official national currencies circulating around the world. Although the number of the independent countries is 197 plus about five dozen of dependent territories. The matter is, that some of them don't have their own money and officially use the foreign currency."[https://www.countries-ofthe-world.com/world-currencies.html] now we have to deal with a lot more, that are seen as a way of investment more than a transfer of value; my point here is that many "smart money" is moving from the regulated stock exchanges to the "crypto world" and that transfer of fiat regulated money can also bring a mayhem in the traditional money system.
Just to finish before I get into other topics LOL, BTC is only the tip of the iceberg of financial revolution in which people will want to have the control of their money and assets 24/7.