>but if the web were content addressed instead of server addressed you could then be serving that cache to your municipality even after it became disconnected from the rest of the internet.
This is already possible without content addressing with CDNs. They can serve content from a local cache even when the host is disconnected from the internet.
And the first thing webdevs did once this became widely available, is change their apps to cache-bust their code; between that, and the short release periods in webshit ecosystem in general, and security and privacy considerations messing up things as usual, the promise of users mostly hitting just local cache with any marginal request, never materialized.