What would an application platform look like that isn’t a ‘document’ delivery platform? In my opinion, the ability of your browser to be essentially the OS of the web was responsible for the second great explosion in usefulness of computers (the first being the PC itself). Mobile apps were the third, but it’s unclear to me if there’s any benefit to rewriting many (most?) web applications as desktop applications. Discoverability, complexity and debugging costs all go up in such a world.
It's hard to imagine given we've been stuck in this world for so long. However, I have to believe there is a better way. Building an app with HTML/CSS/JS just feels like a mess. I'd start by looking at some good ideas from the past... Sun NeWS perhaps.