The geometry would be hard to compress, but I suspect there's some clever tricks with some kind of fractal compression[1] that could drastically reduce texture sizes for camo, foliage, etc. without any effect on aesthetics.
Encoding is the hard part, but only need be done once when building the final release.
> there's some clever tricks with some kind of fractal compression
It's a shame that IFS hamstrung the adoption of fractal compression with their expensive license fees - wouldn't necessarily have been The Future Of Images but at least we'd have had the option.
When I was messing around with this (~1995?), there was a Yuval Fisher paper floating around which did a good job of explaining it. Although it looks like it now costs ~$40 to get that paper or ~$100 for his book. Helpful!
Encoding is the hard part, but only need be done once when building the final release.
[1] https://en.wikipedia.org/wiki/Fractal_compression