Bitcoin being banned worldwide is an absurd idea since prohibiting it would be tantamount to banning the internet itself! Also, if we
could only see the increasing adoption rate and popularity of Bitcoin and other cryptocurrencies, then we can say that it will make it even
more less likely to disappear in the foreseeable future.
This ridiculous idea has been popping up in the past, but one thing the governments of the countries realize is that they banned it too late and even if they banned it, nothing can stop someone else from participating in bitcoin, unless, as you say, ban the internet altogether but that's impossible. In addition, bitcoin is beginning to create some benefits for the government, many countries have been able to gradually accept bitcoin, by the time the government can handle activities from bitcoin, bitcoin will be accepted worldwide