Even CSS is optional, a "semantic 2D HTML document" is enough. You will get a nice layout until the browser does handle a table level of even one depth (and you usually can manage with browsers flattening the table).
Navigation among those "semantic 2D HTML documents" was thought thru already: https://webaim.org/techniques/tables/
That should be enforced by regulation on "critical" (USA: utility?) online services.
It means many could develop reasonably an alternative _REAL-LIFE_ browser to interact with those online services (this is strategic control, and allows money to go where it is actually needed instead of those toxic web javascript abominations, and this word is fair, not nice, but _FAIR_).
If something has to replace noscript/basic (x)html, it should be as simple, or more simple, and as stable in time. It must be worth it: namely "cleaner".
We could compromise with something "javascript": I guess that would be a dynamic 2D RGB canvas with very basic and few drawing primitives (mostly vector based with a glyph renderer) and OS services (probably event based), but I don't believe anybody could come up with that thing and hold it stable and simple enough for much time before the toxic people get their way with it: embrace and extend until control is taken over or until it is unusable and destroyed if control take over failed.
