[orange8]

> It doesn't handle "state" well

It is a markup language, just like the SGML you talked about. In-fact, it started out as a subset of SGML. If it could handle state, it would not be a markup language. The same applies for any desktop GUI that uses a custom markup language to declare a UI.

> via HTML + DOM + CSS + JavaScript + JavaScript libraries to something that natively handles GUI's. Those 5 parts together have proven fragile

They have proven so fragile, that the whole web, billions of pages handling all sorts of things from banking to social media run on top of them. Not to mention PWA mobile apps and cross-platform desktop apps like VS Code. And it is actually 4 parts, all platforms have libraries.

> That's why we need a dedicated GUI markup language and browser (or pluggin).

We already have one, maybe you just don't like it, don't understand it or its not cool/edgy enough for your tastes. It's called HTML.