I think some nations already welcome Bitcoin and there will be no need for government to outrightly ban the use of bitcoin. So if one nation is critical of it, users in that nation will find a way through the internet to byepas that nation regulation. Bitcoin traders will always find a way around the internet to do their investment except the internet is shutdown.
As long as internet is there, bitcoin cannot be shutdown. Some people might think that bitcoin is a bubble and they stop using it but majority of the people and governments will accept bitcoin in the near future. Digital currency is the new form of currency and we have to accept it.