If this is meant to be an "as realistic as possible" representation of ancient Rome, then the level of detail is linked to our knowledge of what specific buildings may have looked like back then. That's why eg some of the statues have a very high LOD because they were preserved until today.

Now, comparing this against a multi-hundred-million budget for-profit video game seems a bit pointless, because in a video game (apart from time and money invested) there's no need for historical accuracy. But if we assume that standards of scientific accuracy apply to this visualization, then it makes a lot of sense that they didn't just invent a bunch of details. Imagine them publishing a paper and just filling some historical gaps with "this is how we think it might've looked"..

Nitpick: Rome was a city with a population of up to 1 million people plus millions of animals. We see a few plumes of smoke coming up from bath complexes, but that would just have been a few of thousands. Even if this was in the middle of day in the middle of summer, we should expect to see plumes of smoke coming up from tens of thousands of fireplaces. How else would they cook, bake bread etc. This was a very dense city, so I would expect to see haze over Rome even at noon in July. I would also expect to see soot on all the buildings and dirt in the streets.

I know this is just a model, but it leaves you with the impression that everything was white and clean, which sort of plays well with the thought of Rome as an advanced civilization that gave us a lot of our concepts and ideas for government and law. But it likely wasn't that pristine. It was probably a dirty, stinky, smoke filled, decease ridden place.

But still a wonderful model. I wish we had had these kinds of videos, when we sat through history classes.

EDIT for tl;dr purposes: the models and textures have almost entirely been developed through public funding over a 20 year period but have recently been trademarked by Bernie Frischer Consulting (AKA Flyover Zone Productions) which this website is serving as a shop window for. Seems pretty sleazy and a bit of a shame to me as: 1) it's a great if slightly patchy resource which sounds like it really should be under public access somehow; 2) a couple of hours in the hands of a decent 3D artist to setup lighting and cameras correctly would do this model so much more justice.

And Circus Maximus ... it could seat 1/4 Million people !! Holy Moly - that's bigger than stadiums today. (different Health and Safety rules I know) but still ... that's insane.

I could forgive the crude, flat lighting if it was true VR but we get the worst of both worlds - low-quality rendering and the lack of presence you get from non-volumetric content.

Hopefully they will improve their offering in future as this is exactly the kind of thing that VR was made for.

https://www.romereborn.org/

EDIT - addressed in their FAQ:

Q: Do you plan to offer open-world VR?

A: Yes. "Open world" means that the user can move at will through the virtual space. At the moment, our users are fixed to a single vantage point, around which they can pivot at will to obtain a 360 panoramic view of the scene. We consider this a temporary expedient necessitated by the frame-rate requirements of the VR stores we use and by the computational limits of some of the VR headsets we support (e.g., GearVR and Go). As soon as the stores change their minimum hardware requirements to the point where our open world apps can meet their frame rate benchmark, we will release our apps in both the current panoramic flavor (which will probably continue for some time to be needed for headsets not reliant on external computing resources) and in the open-world flavor. We definitely want to be the first to realize Palmer Luckey's original motivation in creating consumer-level VR headsets of making it possible to walk down the streets of ancient Rome.