I have a lot of personal theories how my country can best cope with future geopolitical adjustments. If I were in charge, the first thing I would do would be to close most foreign military bases. We can have the strongest military in the world and have them largely based in the US. I think the US Navy continues to be a good investment, but I would cut back a small amount on intel and other military branches.
All these ideas of some kind of blockchain based common alternative is still just a pipe dream. You can’t base a real currency on crypto. If you think you can you don’t understand what currency actually is (hint: currency has never been a successor to metal/coin based transactions… it’s an abstraction over debt and debt has and will always be the main way value is exchanged. crypto cant replace debt based currency because debt is based on trust in humans, something that trust in an algorithm can’t replace)
I share some of your lack of enthusiasm for crypto currencies. Rather, as individual countries trade between themselves it may often be advantageous for them to use their own currencies, especially if they don’t have to hold other countries’ currencies for long periods of time.
Non-US countries pay quite a penalty for holding lots of dollars. I expect every country to do what is in their own best interests, just as I hope my country makes good long term economic and geopolitical decisions.