And when your avian ISP dies, how do you make requests?

If everything you need - application logic, css, media, data etc... - is cached on your device, you can carry on.

You're being far too myopic about all of this. There's many different use cases and solutions, all of which have their tradeoffs. Sometimes ssr is appropriate, other times local first is. You can even do both - SSR html in the service worker with either isomorphic JavaScript, or WASM.

We can all agree, though, that React and it's derivations are never appropriate.