The beauty of what I suggested is that it stops anyone forcing a new standard for something. If a browser vendor creates a new feature then it's up to developers to support it. If they choose not to that's fine. If developers were happy to pick and choose which features to support, and were willing to put in the effort to support different approaches, then Google wouldn't have any power to force change across the whole web. They'd just make something that only works in Chrome, and developers would choose to use it or not.

Exactly, at this point this should be a proposal for standardization with any implementations in browsers gatet behind flags, not something that google is shipping to end users on a whim.