Yes.
The bulk of modern install sizes are media assets.
The actual code to run the game is relatively moderate, it's all the motion captured, fully voice acted, 4k "HD" that usually bloats the installed foot print of your average game.
Procedural Generated Content is very efficient, when done properly, at keeping the amount of raw data low because it creates it dynamically, rather than relying on assets that had to be per-generated and saved on disk.
The game is early access... so the Developer may plan on going back and improving the visual fidelity of basic assets to increase visual fidelity at some point in the future. For now, it's just good to get things working in a playable game.