Nothing is actively stopping it. In fact a lot of people would strongly appreciate it, maybe even contribute. I would really love to see something like that:

- local-first CMS with a strong emphasis on folders/files - multiple DVCS integrations (git, mercurial, pijul) with commit signatures (PGP) - support for forge APIs and email-based workflow to simplify the cooperative PR/MR/patch process - strong translations support, to see at a glance missing/outdated translations

There's been some work in this area, but netlify is really complex and is not meant to be selfhosted. And in any case these CMS overlays for SSGs end up making their own conventions that SSGs then have to comply with. It would be interesting to see an alternative approach where a CMS-as-a-library can be adapted to support any kind of SSG.

Some complicated stuff to deal with when building a content editor for SSGs:

- internal and relative links don't have the same semantics across SSGs, and don't point to the same place depending on the webroot - content may contain macros/shortcodes, the local editor needs to be aware of that in order to produce meaningful output - taxonomies and parenthood relationships also vary greatly from one implementation to another