First of all only a stupid can actually believe that someday internet would shut down for the whole world. Bitcoin runs on 'distributed ledger' and it's now everywhere. So, there can only be two parts of this bullshit movie if that happens-

• Internet in some part is down so people from that part won't transact for sometime. Can people use Fiat in such times in the region? Yes, they can, until they have few notes! But again, if the outage continues even for 24 hours, can all paper trash available in the region sustain the catastrophe? There will be chaos all around. People will be lining outside every bank. There will be protests all around. Don't ask me, the most outrageous protests would be from those who would be refrained from watching their fiat pile up on stock exchanges. That would be an amazing day!!!
• After so much chaos and drama, ultimately, government of that region has to restore internet and people would then run to convert their fiat to Bitcoin and there will be a 'public declaration that Economy wouldn't be handed to statesmen'. The governments could do nothing except accepting the demands of people. 'Those would be days when a Bitcoin Economy would establish for that region.' People will then live happily forever.