Hmm... I see now, it's a bit hidden in the proposal text to be honest that this isn't just static html. I just re-read the text again and don't actually see it spelled out what exactly this will produce. Isn't it "static html" in your definition because there's still some JS libs involved or what is the difference between this proposal and the alluded to "static html"?
Perhaps this needs to become some form of --output-format=something instead then, which would allow doing that static-html in the future? Would the output today be e.g. --output-format=html and the "future" one you are alluding to html-nojs..?
The "static hosting" terminology is just something I find very weird somehow, having worked with many other documentation engines (rst, antora & asciidoctor, godoc, javadoc, paradox, etc.) It's all really just about some output format, and options to configure some base paths, but those are shared really between different formats even perhaps -- a base url is typical for all kinds of outputs, I don't think we need to associate it with "static hosting".
Not sure if this helps, thanks for being open to feedback!