That's fair, but I bet you're not using a static site generator to produce your PDPs. (Or, if so, I'd love to read an engineering blog post about it! Static PDPs would be a solid optimization in a lot of ways, and while I'm no longer in a role where that could be directly useful, it'd still be interesting to find out what challenges a team overcame and how in the course of getting there.)
Most content on our PDPs are statically pre-rendered, yes. Some stuff we obviously can’t of course (e.g. some of the recommendations that are based on your personal behaviour), and those tend to be mini-SPAs. We save from having to re-render everything if, say, a menu item changes, by compositing page fragments at a CDN level and caching the result for a shorter amount of time.
This setup is not particularly unusual for a microfrontends environment I don’t believe.
We did much the same, as I recall. (I didn't spend very much time close to the frontend in that role, so I may misremember, but that description has a familiar ring.)
It's probably about as far as the concept can reasonably be taken; in theory I could see something more like "true" SSR with some probably complex hydration, but the engineering time would likely make it uneconomic to pursue what would likely be marginal benefit.
