> Correctly configured it is a static site with a minimal stub in PHP
Maybe there's a 1001 plugins being used which means the Wordpress site has to make boatloads of requests to the backend. Many Wordpress sites make that mistake. I keep my plugin count to at least five plugins. And they're obviously plugins which I really need, and they're not chatty in any way.
And if you want to go further you can bypass that stub and serve the static pages directly from your web server.
Best of both worlds, really.