I was a web developer 25 years ago and for the majority of projects we only made static sites, all templated and minified. My skills are somewhat "of that time".

Recently I was asked to build a site to demonstrate some new software. It consisted of over 10k pages that once built would rarely, if ever be updated.

I just scripted and templated the generation of every single page hosted it in S3. This may sound ridiculous in this day and age but it takes a few minutes to rebuild and update the entire site.

Guess my point is I don't really find duplicating things to be a pain in the ass

If you don’t mind a little coding, it wouldn’t take long to build a tool that lets you store the bodies as template files, wraps them in the header/footer, and minifies them.

Even less effort is pandoc’s standalone mode which lets you provide a wrapper template.