Fiat will be replaced by crypto currency but i dont think it will be bitcoin. Government want to control everything and even fiat money , bitcoin cant control by the governement so they will create thier own and will use blockchain technology to make a new way of payment before fiat currency fall.
How can cryptocurrency replace fiat if cryptocurrency is not fully controlled by the Government? I dont think there will be a Government that will allow their current currency to be totally replaced by cryptocurrency.
Sure the government cannot control Cryptocurrency but the Government is likely to Crash too
Can you elaborate more on how the Government can crash? Maybe it depends on the power of their currency, if its US, they have a strong currency unlike other currency.