When people get new bitcoins that aren't spendable in certain locations, it will be interesting to say the least. Then the government will force everyone to "accept all bitcoins".
There will be some groundwork done. Powerful people will be coopted. Developers, mining pool operators, exchange operators, merchants, whales etc. Propaganda will be used to convince ordinary users of the need for change. Then there will be a fork and whichever chain gets the majority's support will become defacto bitcoin. Those who persist with the old chain will have their wealth instantly wiped out.
Governments have a history of taking over private property. The Romans used to do it to every noble family that crossed the emperor. They even stole from soldiers who were away fighting for the empire!