This would be great. I also think there is the issue of HTTP being a good protocol and the web being a good distribution platform, and as a result browsers have to be complex because they are everything to everyone. It'd be cool to have a really optimized browser/game engine with WebGPU, WebXR, Gamepad API, audio and Wasm, and no or minimal HTML support as an application platform, for example. Or a browser that has a unified fixed UI for streaming video. I understand these aren't perfect examples and can be nitpicked and might not work in practice, but I strongly agree with this idea in a general sense.