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.
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.
