> Given that Markdown fully supports HTML I have built sites using just Markdown + web components but that's... just how it works.

Agreed. My blog is a single shell script that runs pandoc on all the files in a subdir, generates a new .md file for table of contents, and then uses pandoc to generate a ToC.html file.

That doesn't mean that my the site uses no Javascript - the magic of web components means that I can place `<some-custom-component> ...` in the middle of my .md content and have interactive components in the resulting html.

What would be really useful is decent tooling for this sort of authoring.