It's trivial to generate pages statically, irrespective of the update volume. Instead of updating database rows, just save S3 blobs of HTML.
The reason this is not done is an accident of history that is no longer required but has become the norm.
"Back in the day", browser compatibility issues meant that user agent strings had to be inspected and different HTML content served based on the browser. Mobile browsers especially required vastly different content compared to desktop browser. I don't mean two different kinds of content, but dozens.
Similarly, text encoding variations was a huge pain.
With HTML5 and modern browser standards this is a thing of the past. The same static HTML can be served to everyone. Any content that needs to vary based on client-side metrics is best implemented by JavaScript or CSS, which can be responsive to display changes like phone rotation.
There is literally no benefit to dynamic rendering for many sites. It nearly guarantees scalability issues at the hardest part to scale -- the database. It means that every "moving part" must always be moving, or you get a guaranteed outage. It means that any caching tier like a CDN gets you right back to the pros and cons of static rendering: either you don't cache all of the site OR you have to live with the limitations of static/stale content.
CMS products like SiteCore or Wordpress are especially bad, doing everything fully dynamically. I've seen these products struggle to serve 10 requests per second on clusters of VMs that should be able to serve 10 million.
The most crazy thing I saw was a plugin that did image compression optimisation dynamically with a fixed-size cache on a per-server basis. If you had more GB of pictures than the cache size, you'd get cache thrashing and the CPU load on all nodes would spike. Scaling up the farm wouldn't help either because the new server would have an empty cache and hence would overload its CPUs for hours.
Simply pre-optimising everything and dumping the result in something like and S3 bucket would be orders of magnitude more efficient and scalable. We're talking up to 100 Gbps egress to the Internet, no sweat.