RAW usually compresses, just not as well as lossy. For example, the lossless FLIF image format usually compresses images quite well (and it's lossless - you can binary compare the before and roundtrip images to check).
For video, I suspect there's things like FLIF, but with interframe knowledge, allowing even more compression.
None of these should beat good lossy codecs, but they vastly outperform completely uncompressed data for the stuff people normally capture.
If you somehow capture true random noise, then these wont' work. But most recordings of interest are much more structured, hence compressible.