I often wonder how much of this - at the lower end anyway - is simply driven by poor monitoring. I mean, if your monitors (or analog monitoring path) is noisy when you crank it up a bit, the tendency is to mix "louder" (with DSP limiters and similar) which we all know is a generally bad idea for that particular use.
It's like trying to squeeze out a better analog S/N ratio by pushing all of the digital music up near "Valhalla".
When maybe they just need to deal with the noisy parts of the analog chain... and turn the monitors up for everything.
Looking at commercial music with an RMS of -2 doesn't help. I often wonder what would happen if you feed those signals at unity to a typical cassette deck for recording to tape... what the metering there would look like.