What will happen with Blockchain technology in the next 50 years?
Probably to recesses of government control that you would not wish upon anyone.
Wholly-digital economies are the worst possible for thing for average citizens and dissidents in the modern society, and it will only get worse as you see governments seeking to control their populations with what amounts to an invisible iron fist. You can see it happening now in the UK, US, Canada, Australia, Germany, etc.
Blockchain technology is great when kept out of government control. The bad news is that they will find a way to exploit it and force you into it, whether or not you want to. Better make sure you want to be an even less-valued cog in an even more uncaring machine.
This is why bitcoin and other cryptocurrencies are needed if we want to avoid a fate like that, digital technologies are being used to try to control people in ways we have never thought possible just a few decades ago, slowly we are losing a lot of liberties and we need to fight back and a perfect form to do that is with something like bitcoin but while I have confidence in bitcoin we are not sure how successful it is going to become.