Electron apps have enabled Linux as a desktop platform for many use cases. And while they have drawbacks, I think this trend will only gain momentum in the future.
I see web technologies pretty much as the remaining subset of tech that is not (yet) controlled by a single entity with commercial interests and monopolistic tendencies.
Wouldn't it make sense to go all in with what we have now and create a new kind of desktop OS that is web first (or only) in terms of UI?
An Electron app could easily be retrofitted to run in an environment like this and web content could become a first class citizen in a desktop environment. This would also eliminate one of the primary concerns with Electron, namely that each app has to carry its own instance of Chrome with it. The browser engine could pretty much be standardized and there wouldn't be a need for this anymore. Backends could run securely, in a containerized environment.
I know there's Chrome OS, but what I am talking about is more like an open alternative that doesn't rely on the cloud so much and still allows you to build full-blown native backends. Just the frontend and window server would be HTML5 only and embrace modern web technologies.
At the same time, I feel like the DOM presents us with some hard to overcome performance problems (like single-threadedness), and the current batch of declarative view libraries is actually making things worse (in terms of performance).
I think these hurdles will be overcome eventually – but I feel at this point, the stars are not aligned yet…
Regardless, that implies Google believes your thesis (at least until they shut it down) - that web UIs are far along enough to support a whole operating system.
It's not that the (G)UI can't be done with web tech, it's that the backend has to be native to be fast enough (or rather, not to get users cursing that the software stack is stealing 10% of their system horsepower). That means non-interpreted, non-sandboxed code running on the bare iron.