But it's there, just an abstraction (or many) away. If you don't get HTML/CSS then no framework will help you that generates it. You can avoid JS, but understanding the DOM and CSS best practices is essential. Once you get it, you don't need libraries like this.
Using browser's caching, you can save bandwidth and keep that WebAssembly code from being re-downloaded. Then you can feed it URLs serving your own content in your own compact, logical and otherwise awesome format, and have it rendered.
By that moment you will have reinvented something like Flash, only completely static.
I was expecting something like that from the OP title. I don't doubt however that this technology will come, it's a question of when. I hope they will support text selection :)