I am, admittedly, new to Bitcoin but this question never leaves me. If bitcoin is not a bubble, if bitcoin somehow makes itself the international standard currency, what happens to the people who never bought bitcoin? Will they be provided a timeframe in which they will have to exchange their money from traditional currency to the cryptocurrency before traditional currency is phased out and deemed worthless or will there be another method of transition?
There is no way possible for bitcoin to replace fiat currency. Usage of bitcoin as a currency demands literacy on the part of the citizens, internet services everywhere across the nation and endorsement by the government. It is only when these are available can bitcoin replace fiat as a currency.
But then, there is no way everyone can be literate most especially in developing countries. Most people also do not get access to internet especially in rural areas and most government of the world despise bitcoin and would not accept it as a currency.
So there's definitely no way bitcoin can replace fiat.