The content is copyrighted, so it would be illegal. Besides, you cannot extract the textures as they're all baked into a single giant texture called "Megatexture" in a very heavily compressed format which would take 192 GB RAM to decompress.
Not quite
That's not the same build - you need to pay attention - Carmack keynotes need technical background to understand.
The build they were using in the studio .... they used 192GB RAM server to run it efficiently to actually test the game fully. The so called "super quality pack" is what we'll actually get but it's unknown how many gigabytes of that pack will be released ... maybe 20 GB at first .... and then 100 GB

Compression is made from those 150 GB down to 25 GB
1TB is source .... the source is not the playable version of the game - it's the Maya/ZBrush/3DSMax/Photoshop outputs , those are not loaded by the engine directly, so the assets are compiled to a 150 GB .... then this compression kicks in and makes it on 3 DVDs that you play. This compression makes these bad texture resolutions. They were also doing all they could to preserve more detail while lowering size.
The in-game decompression happens in real-time ... that's a complex topic which i cannot explain as im not sure at this moment my self how that carmack said, i know it for my self but im worried i'll describe it wrong so ... just watch the keynote , i did 5 times.
The final compression is the setup compression which gets it down something like ... 6 GB more ... at least on the PC since CPU is not an issue and they could ramp it down from 25 GB to 18 GB for the setup. That's a "packing" compression that has nothing to do with the in-game realtime texture streaming stuff that does the DTX decompression.
That's why it takes so long to install the game because the decompressor has so much work and you actually hit your CPU bottleneck on the X360. But the X360 game was not compressed as much as the PC version , because they compressed only as much as they needed to hit the 21.6 GB space they had on 3 X360 DVDs.
It's really - they did so much to make it as best as they could - the game design or drivers issues has nothign to do with this - Rage is a technological marvel. And Doom4 will be even better IDTech5 version. (new GPU engine, voxel/geometry virtualisation maybe, super script, dedicated servers , full MP , etc )