i agree with the points made.
2 channel guys (who make up a great majority of audiophiles) would probably not agree, but headphones allow for much greater analysis of upstream gear than speakers.
with my Harbeth 2-channel rig, i am perfectly happy with my current gear.
i have switched gear out with other gear over the past few months, and the differences were subtle but noticeable.
this basically let me know that money would not be wisely spent to buy something uber high-end for that setup...
however, with headphones such as HE-500, HE-6, LCD-3, and HD800, i have been able to appreciate ongoing upgrades in gear, and as a result have heard detail retrieval, noise floor, soundstage size, smoothness, etc. all improve over time with the same headphones.
i am sometimes amazed at the positive reviews some gear receives in popular publications. especially source gear.
gear that i have tried out with headphones and been sorely disappointed with.
my guess is that the reviewers' 2-chanel rig sounded quite nice with this gear.
but it's not good enough for summit-fi headphone rigs.