Maybe something that adds to this low demand is that: 1. Web pages that are developed from the viewpoint of the user having JS, makes it trivial to implement something that provides the same results. 2. Web pages that are developed for user agents that don't run js, probably want to have some interaction, so already have a server runtime that can provide this feature. 2b. And if it doesn't have any user interaction, its probably a static content site, and nobody is writing content in HTML, so there already is a build step that provides this feature.