Western countries (USA) often have rich economies, which means that the average person in said countries often has better access to high amounts of storage than people from impoverished countries. This makes it so it's not a priority for companies targeting that audience to optimize for disk space.

TLDR: Rich countries get beefy PCs, which get unoptimized games

I think the OP's explanation is the real one, but I still like to think this is a thing where more than one thing can be true

Not making excuses for every instance but in the vast majority of cases, optimizations are done by making trades between runtime performance, RAM usage, and disk space. Of these, disk is cheapest. You might optimize something and end up using more disk space as a result.

For example not all video cards support compressed texture file formats (though gaming hardware is likely to be close to 100% now....) so you might store texture memory uncompressed on disk (bigger size) to save on the decompression needing to happen on the CPU before transfer to the GPU.

He uses Arch Linux BTW.

In it's early days? My nephew played that a long time ago. It filled his PC. I thought it was mods. As in, the entire game would clone itself when it created a mod profile. I don't think it does that anymore.

I've never understood that weird market... Why the fuck is anyone buying that shit?