Full nodes have financial incentives to run and they do so today at a scale that rivals the internet. It’s not a favor to Bitcoin, it’s a business. They would only stop if the financial incentive ceased to exist. I can’t think of a reason node operators would cease to care about their own financial well-being. That’s baked into our species.
Note that your reservations apply equally (and potentially more so) to fiat. USD is a virtual currency. Cash is on the way out. You will not be able to spend your USD offline. USD is based on a network of centralized banks. You cannot spend your fiat without a computer asking permission from these centralized systems.
The world stops if the internet stops. That’s not a Bitcoin problem. Bitcoin actually improves on the state of things by replacing encumbant authorities and centralized computing systems with math and a decentralized network.
I’ll add this. It’s not the current state of the world, but there is a very real chance Bitcoin can be made available off-internet via a satellite network. This would prevent state-level censorship like what we see when authoritarian regimes cut the internet.
https://github.com/Blockstream/satellite/blob/master/README....