games will only get bigger, not smaller. compressing a game down to something manageable and keeping the quality up is a fantasy.
RAGE's textures are an entire terabyte, yet John Carmack put some serious loving work into a compression algorithm to get them down to a measly few gigabytes.
Ideally in the future more development studios will work on compression within their game files. Most already use data packs, but they don't compress the files, only encrypt them.
It should be noted; the most heavy files in any game are textures and sounds. 3D Models, BSPs, animations, data files (such as configs, string databases, script files, visual effect definitions etc) and executables are always really low file size compared to those.