I agree. If we want an application platform, let's have something designed first and foremost to be an application platform instead of the garbage fire we've bolted to the skeleton of HTML.

Here's how you do it: create the new platform and its spec. Include an open 'document rendering engine' to replace that portion of the web. For backwards compatibility, go ahead and port a web browser to the new platform. For forwards compatibility, port the new platform to the current web.