I don't disagree, but again, 9 dB below reference at 1m without any eq. This equates to 15-17 dB below reference with the 96 dB distortion sweep shown. With 3-6 dB of eq added below 3 dB, which will be nearly guaranteed, distortion will be much higher than the graph above, and we are still 15 dB or more below reference level.
Again, I think a lot of this is perspective. For example, my previous setup consisted of Hsu HB1 MK2 L/R with HC2 center. channel, powered by Yamaha RXV-375 AVR. By -10 MV, it was painfully loud and would run you out of the room. Upgrading the AVR to Denon X3300 seemed to raise the loudest comfortable listening level by a few dB, likely due to a fair bit more power.
After the Hsu, I ran a pair of 94 dB 8 ohm horn loaded compression driver speakers. At -5 MV, listening levels were quite comfortable even for my wife who is more sensitive to loudness. I now have 91 dB towers and its enough capability for things to sound good up to my loudest listening levels. But I have no doubt that when things start to sound too loud, it is in part due to lack of clean output capability, whether it be distortion from the speakers, compression, clipping, or some combination of all three. I would never have thought so had I not experienced first hand how much more tolerable things are with more capable equipment.
That's one of the reasons I'm not totally ruling out the option of a good 3/5/7 channel amp like the Monoprice Monolith, just to get a few more dB of clean output capability for those very spirited listening sessions.