Nobody can shut down the internet,because internet is a network of servers.Can you shut down all of them?
That's why nobody can shut down the blockchain.As long as there are miners,the blockchain will continue to exist.By the way,bitcoin can be printed on paper.Nobody is saying that bitcoin will be 100% digital.

We already have a global currency.It's called US dollar and it's a pretty shitty global currency.

You can shut it down in parts of the world, or even in a country. The internet is centralized at the moment, this is the problem. And something some people are trying to fix. If you decentralize internet, like Bitcoin with nodes distributed all over the world, then sure,,, you improve chances of servers always able to send and receive information requests.
Bitcoin is digital make it on paper does not make it physical,,, or does it? I am confused.