You have completely misunderstood the proposal. None of those drive OS native UI widgets through markup and scripts downloaded from the web.

Ah no I was just being snarky and not at you. We're all missing (hyper)text markup language as the UI markup layer, plus js. We previously had some kind of alternative "load app from internet" but the runtimes were external (and provided lots of fun security holes).

I completely agree it would be better to rethink what we want and have markup/code/etc optimised to the task of rendering applications. I don't think it'll happen unfortunately.

Java applets drove native widgets in their first iteration. It wasn't markup but that hardly matters, you could have easily slapped some XML over AWT and the difference between a .jar and a .js isn't big.

They had to stop because native widgets aren't secure enough.