2. Vast library of plugins
3. Lets you focus on content rather than twiddling bits.
4. Open source, php/mysql, you can host it anywhere.
5. Vast number of devs who know how to make changes to it.
6. Most of the functionality you need for a basic website, including: scheduling content, WYSIWYG editor, ecommerce (via plugins), integration with analytics, custom data types.
7. Did I mention it just works?
At least I haven't found one for Jekyll and 11ty, the two SSGs I have worked most with. It seems an architectural limitation of the SSG model.
All I want to do is to say "This blog post is ready to go on Jan 1, publish it without any action from me." Trivial in WP. People talk about cron, but really? I'm a dev, I can handle cron, but it seems a bit much to use to schedule a blog post.
But SSGs have a different set of design tradeoffs (the lack of a WYSIWYG editor being another piece of functionality that seems to me to be core to a CMS), so maybe I just need to accept that.
I don't think SSGs are all bad, either. I wrote a blog post a few months ago talking about the tradeoffs: https://www.mooreds.com/wordpress/archives/3369