In many deployments, Wordpress started out as just a blog that is easy to edit right from the web browser, but then grew into way more. Most commonly, people end up retrofitting all kinds of e-commerce features onto it, and that's how you really get into the whole plugin mess. At that point, for better or worse, the Wordpress instance is serving important business needs that are not addressed by a static page.

It went from a blog, to an entire CMS. Which is bonkers