my only option to fix this are javascript, xslt or a server side html generator. (and before you ask, static site generators are no better, they just make the generation part manual instead of automatic.)
i don't actually care if the site is static. i only care that maintenance is simple.
build tools are not simple. they tend to suffer from bitrot because they are not bundled with the hosting of the site or the site content.
server side html generators (aka content management systems, etc.) are large and tie me to a particular platform.
frontend frameworks by default require a build step and of course need javascript in the browser. some frameworks can be included without build tools, and that's better, but also overkill for large sites. and of course then you are tied to the framework.
another option is writing custom javascript code to include an html snippet from another file.
or maybe i can try to rig include with xslt. will that shut up the people who want to view my site without javascript?
at some point there was discussion for html include, but it has been dropped. why?