Jeremy Keith built a static archive of his site The Session:

I wanted to reduce the dependencies on each page to as close to zero as I could. All the CSS is embedded in the the page. Likewise with most of the JavaScript (you’ll still need an internet connection to get audio playback and dynamic maps). This keeps the individual pages nice and self-contained. That means they can be shared around (as an email attachment, for example).

Not everyone can code something like this, so more web platforms should have this as a built-in feature. Micro.blog has multiple exports with just plain HTML.