When debts of countries will be estimated in bitcoins we may say the replacement began successfully 
We may not live up to that. Governments didn't drop gold to get caught with Bitcoin
Bitcoin doesn't have the power to replace dollar in any way. But yes, it may replace zimbabwean dollar as their economy is shattered. Jokes apart!
However, bitcoin and paper currency are genetically different. Dollar is a government backed currency where bitcoin is not. Bitcoin doesn't have any central authority. It is backed up by public trust. It will never be able to replace dollar or any other fiat currency unless and until any country adopts bitcoin as their national currency
However, bitcoin and paper currency are genetically different. Dollar is a government backed currency where bitcoin is not. Bitcoin doesn't have any central authority. It is backed up by public trust. It will never be able to replace dollar or any other fiat currency unless and until any country adopts bitcoin as their national currency
The Zimbabwean dollar has already been replaced
With the US dollar if you didn't notice. It was also "backed up" by the central authority but it didn't help it since folks started to massively use anything until the local currency got completely abandoned. Or do you really think that a government is going to accept payments such as taxes in the currency that no one gives a fuck about any longer?