It's hard to imagine new revolutionary ideas that will come in the future. In my opinion crypto currencies was already a big step into the future and it could the final step towards a fair monetary system for all people. If something is good and working for all people, no need to find something new again. Thinking within borders and small countries is wrong for the 21 century, we should be focusing on the world itself and stop with the dividing and exclusion of people. It might take a few more hundred years, but eventually the world will unify. The question is than what kind of currency will be used that is valid all around the world. Crypto currencies would be the best option.
I wouldn't be able to imagine bitcoin neither, but it happened. I am sure that people never really imagine what could be possible until it happens and then when it happens we became accustomed to it. If you told me 15+ years ago that there will be some digital currency that will peak at 1+ trillion dollar market cap and 68k+ price, I would have mocked you, I would have tried to humiliate you.
But at the same time, we are living in that period right now and you would have been right. This means that there could be some people who are considering something and people could be mocking them today, but in 10 years that mocked thing could become something regular.