For me, the argument that a system played at 70 something dB is the height of resolution and therefore, audiophilia, has always sounded more like some sort of perverse blend of arrogance and defense mechanism on the part of its devotees.
The Equal Loudness (Fletcher-Munson) curves are such that if one listens to a 1 KHz tone at 70 dB, the corresponding 100 Hz and 10 KHz tones would need to be almost 80 dB to sound as if they're being produced at the same level. Reverse that, and if listening to those same 100 Hz and 10 KHz tones at 70 dB, the corresponding 1 KHz tone would need to be played at about 55 dB to sound in balance. Given that tone controls are considered anathema to the audiophile experience, it certainly wouldd be rare to see a system capable of that much correction - not that we'd even desire it.
I personally don't demand a high-end audio system be full range in the truest sense of things, but 100 Hz and 10 KHz are frequencies I most certainly consider fundamental. And while I know plenty of people who do, I believe one who listens at less than 80 dB, where the frequency spectrum is beginning to come into balance, is truly kidding themselves in trying to wear the badge of "audiophile". That person leaves an incredible amount of music outside of what is actually taken in. They may like the sound being produced, and the music may possess true and deep meaning, but it's the antithesis of reality, or even high-fidelity. At 85 - 95 dB, things have evened out nicely, and that is probably what could be considered a sweet spot.
By the way, very few people realize that OSHA recognizes the Fletcher-Munson curve, and set its guidelines (levels for which a person is not at any statistical risk for noise-induced hearing loss) for loudness in accordance with it. Beyond that, the SPL/time ratios (I think most of us are safely inside the lines) are as follows:
85 dB for 16 hours/day
90 dB for 8 hours/day
95 dB for 4 hours/day
100 dB for 2 hours/day