Well you can get to a perfect 10k hypothetically, you can have more geometric/texture/lighting detail than the eye could process. From a technical perspective.

Of course you have the technical capabilities, and that’s part of the equation. The other part is the human effort to create the environments. Now the tech sometimes makes it easier on the artist (for example, better light modeling in the engine at run time means less effort to bake lighting in, and ability for author to basically “etc…” to more detail, by smoothing or some machine learning extrapolations). Despite this, more detail does mean more man hours to try to make the most of that, and this has caused massive cost increases as models got more detailed and more models and environments became feasible. The level of artwork that goes into the whole have of pacman is less than a single model in a modern game.