The problem is no one ever built one that works for normal people.

Most Wordpress sites are not operated by programmers, they are run by non technical people who just want a wysiwyg editor and a save button. While static site builders ask you to write markdown files, compile the result, upload it to a server, and if you want to collaborate you have to add git to that.

There almost needs to be an admin app which presents a Wordpress admin like ui but has no public exposure, and then it compiles the site to dump on s3 for the production. But as far as I’m aware no one has built this.

https://jamstack.org

You're describing the Jamstack or headless CMS concept verbatim.

Movable type was the most popular blogging software in 2003 and it was essentially this. An admin app written in Perl that spit out static files.

It is kind of surprising that no one tried to do an updated version.

Is this not it? https://pagescms.org/

Yes, you are right and I agree, there's little empathy with non-coders generally.

Pour one out for FrontPage

City Desk. Where is Joel when we need him!

I mean, github pages using the github editor to edit docs pretty much fits that bill