Earlier quoted context omitted.
You should check out Gemini[1]. That's basically how it works. [1]: https://gemini.circumlunar.space/
Gemini sets a good example, but what I’m specifically advocating for is an incremental improvement to how we use the existing web. Fixing e.g. [1] (falling back to plaintext) should be trivial, and with that obstacle removed there would be nothing stopping early adopters from publishing in markdown today. [1]: https://bugzilla.mozilla.org/show_bug.cgi?id=1319262
Plaintext infrastructure; readable markup; optional (semi-automated?) styling from there.
(Perhaps your higher-up comment already suggests as much.)