@Moon then we have drafts of that in Java, or something like Squeak or image-container management?
The "web" part, from my perspective, is everything between the purpose (presentation) and provision (servers.)
Distributing fat clients: what becomes of the document thing? Is a word processor / old school browser a tool distributed with the document content in your scheme?
The problem we keep hitting is that a neutral platform is built on the lowest common denominators.