It's a matter of convenience and eco-system. Here on HN you can see comments of people praising all the various static site generators (SSG), yet basically all of them require you to run some CLI, copy around files, manually fiddle with some theme and then awkwardly upload the files somewhere. People will praise that it's Markdown and integrates with Git, which misses the day to day use case of 99.999% of people when it comes to websites.

Want to have some interesting facts, links, images, etc. in a sidebar, but only for some pages, etc.? The static site generator goes up in flames or needs a lot of manual tweaking. In WordPress and any other CMS it's either built-in or one plugin install away.

Want to edit some published page, create and preview something new? With SSG you need to make sure you have the latest version locally, then edit the file, create a new commit or copy the file, push the change, wait for some pipeline to run and only then will you see the actual result.

Don't get me wrong SSG are great, but they are solutions for very technical people who like to fiddle with workflows and automations. If you want a WYSIWYG and one-click install experience, you end up with some CMS.

And that hasn't even touched the whole web shop integration topic.

PS: My blog runs on WordPress