You should know that the world economy is based on fiat (Like, Dollars, Yen, Euro...ect ) so it is not that easy that cryptocurrency will replace Fiat especially in the near future despite this new era has a lot a characteristics or advantages. In addition to that, the governments are rejecting the recogniztion of Bitcoin despite they are investing in cryptocurrencies but indirectly , there are too many hiding information and facts, and unfortunately we only see the fake media news. Possibly, after some years everything is going to change in a good way but not now maybe after many years.
Cryptocurrency can replace currency but it will not be able to replace the dominance of the fiat money system because, even if the state is required to follow technological advances, the choice will be to use a centralized stable coin and can be controlled by the government of a country. Second, when we want to have a cryptocurrency, we have to exchange our fiat money with cryptocurrency, so that the gap between the rich and poor remains, only the change is the shape of the rich. The rich can have more cryptocurrencies while the poor have less cryptocurrency.
The problem of inequality in the spread of technology, I think along with technological advances that correlate with the population demographics of a country, the gap will decrease because projections of millennial generation increase while conventional generations decrease.
But keep in mind that the dependence on technological advances is also vulnerable to system malfunctions that we cannot predict due to natural disasters, so we need manual operating instructions and a backup plan if we suddenly return to the ancients because of the loss of technology.
