Check your lexicon as regard to the meaning of crash in the cryptocurrency vocabulary. Bitcoin crashes and has crashed so many times, but after each crash it still takes up to bull market.
Yea, since there is no central government in the world, the governments of the world would never agree and speak with one tongue. While the government of China bans bitcoin and bitcoin related activities, the government of the US will adopt bitcoin and verse vice.
And also, government as an entity might be against bitcoin but the individual persons that make up the government might be involved in bitcoin in one way or the other. So bitcoin will last as long as its chemistry permits.
LoL, yeah, but crash. I mean, I guess you should know I am referring to dying off or an absolute crash that leads to total disaster in a way that nothing can be done to bring it back. I don't just mean the price crash, like that of 2011 (Bitcoin fall by -99%). Someone made a topic here saying it's a Bitcoin obituary, but look at Bitcoin today, still waxing strong.
But anyways, your scenario is just what I am talking about: before bitcoin can fail to exist, the whole government and rulers of every country, city, community, and village will come together and host a meeting to agree that no one should be allowed to use bitcoin in those countries or villages. If not, nothing like that will happen. Bitcoin has experienced real downtime, but it still bounces back.