Really interesting post thanks. Even as an audio novice I've noticed the terrible loudness trend in music, particularly in Foo Fighters releases. It literally makes my ears tired.
Older recordings from the 70s (perhaps early Kansas) have a different sound (not such harsh compression), so the snare drum has a sharp crack on them and they sound like this: CRACK
To get that "sound" Foo Fighters layer distorted guitar on top of more distorted guitar (they use Vox AC30s apparently!). Doing this does make it sound thick but you'll get tired listening to an album of distortion. The bass is also distorted (a tube/valve amp in use). Then Dave Grohl will resort to shouting all the way through the song (In Your Honor was the worst), so his added edgy raspy voice will be added to the distortion soup for maximum distortion.
Listen to some Deep Purple or Led Zeppelin and compare the snare sound to the Foos. Led Zeppelin is a good example because even though Led Zep 1's drums were only recorded with 2 (or 3) microphones, there is real dynamics in the drumming (listen to how the drums come in on Good Times Bad Times). You can tell how few microphones were used because the panning on the drum fill for the toms at the end of How Many More Times pans the entire drumkit, not just the toms. Modern setups would perhaps have close-miked drums panned around the stereo image so as the drummer does a fill on the toms, it doesn't take the entire kit with it (8 microphones for a kit, one for each drum + hi hat and overheads).