You're right.
My definition of audio excellence is very simple. It has to be effortlessly transparent, dynamic and engaging. To my personal taste and standards of cause. Unfortunately, I'm having a really hard time reaching those goals with my headphones setup. And I don't believe that my rig is particularly locking so maybe, I am aiming for impossible. Perhaps it is the scale, more believable soundstage and room reverb qualities that add to my speaker setup realism???? Still trying to understand it and make the most out of it.
My comment regarding DACs is strictly based on typical headphone setup. Since my own DAC performs double duty, feeding both, headphone and speaker setups, I don't feel all that guilty about its outlandish cost. Surely it's not the most refined or sophisticated piece of hardware out other, but for me and my needs, it is more than enough to enjoy digital side of audio reproduction. And I guess, that was my point. For many, DAC around +-1K range would be more than enough to get really close to that last 5 percent of extremely expensive, boutique type products. Also, from my own experience. Those boutique brands add their own spin on sound signature and presentation qualities. It is kind of a necessity as there is a need to differentiate their own stable from its competitors. But I do agree that more money will get you improvements in areas such as soundstage, image, lower noise floor and transparency. With system revealing enough, those nuances are quite apparent. And if budget permits, well worth it.