Being a naysayer is no fun so here’s a positive question: given you know that your website’s speed is bound by network and not compute, what crazy sites could you build? What could you do with a WebAssembly + WebGPU stack that isn’t being done?
Many things are moving to the browser, I wouldn't be surprised to see CAD or video editing running in a browser. They could then be OS agnostic, collaborative, introduce some kind of versioning instead of the project_v3_final.psd chaos.