What you say would definitely work for front-end features – the kind of things that could more or less be implemented by extensions already. It would not work

What you say would definitely work for front-end features – the kind of things that could more or less be implemented by extensions already. It would not work for back-end features, such as WebVR or WebAR, for instance, or WebPay, or WebGL, or wasm. All these features need low-level support and low-level patches that only Google may decide to accept or reject. For the moment, Google doesn't seem overly interested in WebVR/WebAR, for instance, so it doesn't seem that any of the Chromiumlings will be competing on that field.