It is possible that someday all country accept Crypto Currency and it will become Universal Money?
I don't think it's possible for all countries in the world to accept one universal money, but it's possible for all countries to support cryptocurrency and use a stable coin for transactions within the country. The universal cryptocurrency as far as I'm concerned is Bitcoin and several individuals and companies accept it as a means of exchange in most countries. The government may not support bitcoin due to the volatility, but businesses and institutions accept it worldwide.
I agree with you, the idea of having a universal money would go pari-pasu with a universal government. I personally won't like to have a universal government in all the world. Crytocurrency could gain greater acceptance in the world and many more people and government may support the industry in the near future. Let's keep our fingers crossed and hopeful for the best.