Gaming

I’m not a game dev, but from my modding experience it depends on the game.

MOST of the games that have these insane file sizes actually do it to cut down on processing and on load time and reduce pop-in. If a texture or level doesn’t need any decompression, it loads faster. So entirely depends on the asset. So a lot of games do still compress textures. That’s why there’s a discrepancy between the data downloaded in steam and the actual runtime storage requirement.

The 3D models themselves are usually lower space. As is dialog and audio. Though all of those will be mildly compressed probably.

Texture block compression exists, and some of the available algorithms have fairly little impact on rendered visuals.

As you noted, asset scaling also exists in various forms, from mip mapping to audio codecs to alternate asset packs. Imagery intended for 4k and 8k displays is wasteful for people gaming in 1080p, let alone 720p.

The techniques required to cut down on bloat are well known. Some games just aren't using them, or aren't using them effectively. There's definitely room for improvement here.