Earlier quoted context omitted.
I totally understand your take, but as a guy that spends most of his time on side projects working on single HTML files, I have a different perspective. I find the totally self-contained nature of them very appealing because it travels well through space and time, and it's incredibly accessible, both online and offline. My current side project is actually using a WebDAV server to host a wide variety of different sing…
Out of curiosity why WebDAV vs loading the HTML straight from disk wherever they are and having a service that's only needed to for saving changes? Edit: I sketched out a basic version in JS + Python, it's fairly ok to use. The nice parts about this approach is the HTML files are viewable without any extra services, and the service that enables saving doesn't itself need configuration or to keep state.
The downside is even though you know the current directory due to window.location the API is written in the way it assumes you either want a default location like "desktop" or need the user to navigate to the directory before you can do operations on it (for security reasons) even from a local context. The user needs to select the directory once per fresh page load (if you've dynamically reloaded the current content then multiple saves need only prompt once so long as you save the handle).