I have whole rants about this, based on bitter experience trying to convince marketing people to stop using WP and just use a static site. It comes down to ease of editing. A WP site optimises for the editor. Not the hosting, not the tech folk, not the accountants, and definitely not the reader. The people who edit the site get to say how it's implemented. If you give them the choice (as I have) between a site that r…
But if you use Hugo, Ghost, or whatever, you get to the point of "for this you need this other platform", where platform is shopify, or an accounting system, or a social network/membership plugin, a job board, etc. Wordpress became this thing that can be turned into anything else.
So someone calls a consultant and says I want this, and they go, I'll set it up for you in Wordpress. Then, because everyone was using wordpress, it was easy to get people to help you when you had issues, or to tweak your plugins slightly, add a hook to send an email, etc. So the age of PHP consultants gave Wordpress it's dominance.
Problem is, most of these solutions, even paid ones, are not full solutions. When you start using them you quickly realize Wordpress imposes non sensical limitations. You can't architect your online store outside Wordpress's performance disaster of a entity/metadata system where any reasonably sized query takes 5 seconds and generates 50 other secondary, non optimized queries. Some plugins even try to work around this by going around wordpress and creating their own db tables out of wordpress's control.
Wordpress is horrible, not architected for anything other than a blog, but used as a tool for everything. Other CMSs don't do that, so people don't use them.