Then everybody got tired of waiting for their sites to rebuild every time they changed something and switched to WordPress, which wasn't static. Suddenly your changes showed up right away! Hooray! Then everybody got tired of WordPress falling over under any load stronger than a stiff breeze, so suddenly static site generators were in fashion again.
If you think of approaches to building a content management system as a continuum, with purely static at one end and purely dynamic at the other, you can see the entire history of the segment as a series of oscillations along that continuum. Each approach has drawbacks, but the drawbacks of the approach you aren't using always seem minor while those of the approach you are using seem painful, so the market just bounces back and forth between them ad infinitum as people rush to discover if the grass on the other side of the fence is really as green as it looks.