More proprietary than "basically Google just tells everyone how it's going to be"? Maybe. It'd be hard to make it worse though. What people seem to really want out of the web is a VM platform and a document layout engine, so why not design a new VM that is intended first and foremost to be an efficient application platform, and then make one of those applications an open source document layout engine? You don't have to be married to HTTP and all its woes either. You could even port a current "legacy" browser to it. And if that document layout engine is found to be lacking, we can make a new one without breaking everything because its just another application on the VM.
Hell, you could compile the VM with an HTML5/JS target and get forward compatibility too.
A worse standard is unlikely to win people over. Even a better standard is unlikely to win.
Take HTML, JavaScript, and CSS, remove 90% of the cruft. Now, include what people want like a much better table element that by default can handle Adaptive screen sizes etc etc.
Chromium and Firefox are open source so you can probably get support in them by writing the code yourself. But, good luck gaining traction.
