“Wut if the internet goes down!” is the dumbest FUD there is. People who say that have no clue how complicated and anti-fragile (by design) the Network is. 
Discussion
there will be missiles in the air before global internet goes down..
then a single surviving bitcoin node can reestablish the chain history after the caos..
Internet is decentralized by nature and we should use this fact to our own advantage
There’s always FUD… always risk.
The blockchain could be updated in a lot of different ways, it could also change hands in hardware wallets and other forms.