> We've gotten so far away from semantic documents so we could build "apps".

Exactly. We're still pretending that the browser is some kind of document display application when it's an application runtime. We keep adding more HTML tags and infinite number of CSS properties and features (that never get it right) when what we should have as a better application GUI API. Throw all the hardware acceleration and threading into that instead of @starting-style, transition-behavior: allow-discrete, interpolate-size: allow-keywords and ::details-content and breath some sanity into the platform.

We've effectively re-implemented that desktop/mobile GUI using a bunch of cobbled together technologies and continue to get more esoteric and complicated every year. Hell, I'm not even sold on JavaScript -- it's just as clunky and weird as everything else.

Move document rendering into high-level implementation on top of a better designed low-level API much like how PDF display in browsers is done with JavaScript.