

It’s mostly textures, video, and audio.
The game code is probably less than 10gb
Change languages in your game, I am willing to bet it doesn’t download a language pack for whatever language you choose.
You need multiple textures for different screens, resolutions, etc. to provide the best looking results. Multiply by the number of unique environments…
Additionally, it’s not like they can only use “high” or “low” assets, as they progressively load different level of detail assets depending on the scene or distance.
Same with all of the video cutscenes in games, they play pre-rendered videos for cutscenes.
Put a fan in it, you have space