some countries may ban BTC but there are also some countries that accept BTC as a means of payment. In the past, there were several countries that banned cryptocurrencies, but until now BTC is still valuable, this means that BTC cannot be destroyed. I am sure that in the future BTC can be accepted by all countries as a medium of exchange and means of payment.
BTC relies on the free market and that principle can and will never be undermined.
If someone thinks it can happen, point them to the prohibition era. The time when the US government tried to stop people from drinking alcohol but since so many people wanted to do it it was impossible to stop them.
We just have to hope that people will like to use BTC and stand behind it. As long as they do it will be impossible to stop but when it becomes abandoned by its users the government won't have to do anything. BTC will die on its own.