We’ve been thinking along those lines a lot lately.
SketchUp Web is already a “Principled Web App” which means you can install it to your Desktop and have it act a bit more like a native application (no browser window decoration). That is how we distribute SketchUp for Schools on the Microsoft app store. And WASM performance has increased to a point where the modeler can (in theory) be just as responsive in browser as when running natively.
On top of that, we are currently investigating an offline mode for the app. And with the way web APIs are going, someday you might be able to open/save models on your own hard drive, use touch/stylus input, etc.