Maybe in 5 years one or two of those BigCos will be humbled by an upstart, or the state, or the market, or a previously humbled BigCo (cough Microsoft). Then, by necessity, their design systems will become once again driven by the needs of actual users and developers. That's the underlying pendulum.

I'd bet on the next UI standard being a cross-platform library. Electron-like, but with much more efficient stack, and with binding to multiple languages.

I'd bet on "if you can't beat em', join em". Reactive component-based architectures a la React/Vue have won. The DOM has won for the view layer too. And with wasm, you get your bindings to multiple languages. See: Blazor (it's just the first, more are coming). As for desktop apps that could benefit from proper concurrency, lack of a browser sandbox, full system access, etc. - server side Blazor is quietly pioneering a weird new paradigm - essentially running a headless browser in a regular process with full privileges, and then only doing vdom diffing inside the browser.

> The DOM has won for the view layer too

As a front-end dev, I'm not entirely sure I agree with that. The DOM has some annoying performance limitations, and I'd love to be able to use something better for rendering. I think what the DOM has shown, is that cross-platform and the ability to easily do custom look and feel are crucial.