Why not? Everything is possible now with cryptocurrency. 16 years ago, people were laughing at the idea of decentralization and no-party transactions, but people are welcoming it now.
For this to happen, we should have a country to model it, and it will cause a domino effect, but expect resistance from the government. But if you ask me, I prefer coexistence because there will always be sectors or countries where its not possible for its people to live only on cryptocurrency.