I translated the interview from famitsu, and we actually got some nice reasons as to why GT7 looks the way it does, and just how talented PD really is (on the graphical front), because it seems this is a VR game from the thoughts to the practice.
Were there any difficulties in making Gran Turismo 7 compatible with PS VR2?
Yamauchi : In fact, support for PS VR2 was something we had in mind when we started developing Gran Turismo 7. In other words, it was originally produced on the premise of corresponding to VR.
This is just my imagination, but it seems that many titles are retrofitted with VR support. However, we also had a hard time with Gran Turismo Sport, and it's very difficult to make an existing title compatible with VR later.
Therefore, "Gran Turismo 7" was created in advance as "VR Native". Think of this as almost synonymous with running the game at 4K60p (*). In order to move the image with that image quality and speed, you have to make the data fairly light.
Therefore, the most difficult aspect of development was maintaining the image quality without increasing the load when moving the image. However, thanks to that, the support for PS VR2 proceeded smoothly.
*this kinda explains how simple the environments may seem at first.