As we can see now everyone/every developed nation is moving towards digital currency. In your opinion how much time is required for digital currency to take over the current/existing market or it is impossible that digitisation will never be successful. If yes what are those factors ? In my opinion those countries which are not accepting digital currency, are doing wrong. They are only thinking about the tax. They are saying that we will not get any tax and digital currencies are fake. Fraud is very easy in digital world (that is true but it also happen in every market). Although when someone is doing business in digital currency then that person is bringing money to country that is beneficial for the country...
I think its hard for digital currency to take over because all the areas in the countries are fully spreaded with internet connections and aside from that the systems of many stores and establishment are not yet ready.
It is modern age and I have never heard about any such place where internet is hard to access so I really think bitcoin or digital currency will take over, I recently saw a post by a person who was saying that he use to live in back ward village but still bitcoin is being use source of payment over there so, I think it is not so far when we will be able to see digital system of payment in every corner of the world.
Indeed, internet is so effiecient in this era hence the accessing crypto is not a problem however, the things is there are still some places in this world has lack of tools or medium to access this crypto. It'll take times for bitcoin to be used throughout the world yet, I don't think so that this crypto could take over fiat because it is very impossible to happen, maybe it'll just become an alternative mode of payment.
You are thinking it because you have no idea of the coming era. Just think 30 years ago, who could think of cellular phone but today everyone are using it. Just like that today we cannot imagine the coming situation of currency market but the future will show us that digital currency take over the market and the whole world is using just one currency for their daily needs.