@raesco -
There is another way to look at this all which puts diminishing returns in a very different light. We commonly refer to diminishing returns in relation to cost of a singular things, like a car, or a DAC, or an amp. In the audiophile world, very little in truth separates the differences in sound quality between a very affordable DAC as example, from highly priced offerings. It is the typical case in fact, that the most highly vaunted components offer a mere improvement of perhaps just a single percent and a half over less regarded ones. This one and a half percent of realism gain for the huge amount of dollar spent is what typically informs the phrase, diminishing return, which, for each item, component, or room acoustic correction measure taken alone, may be too small to even detect without A/B/A test listening. The most dedicated audiophile, however, will research as much as possible to ensure the greatest value for the dollar, and who will spend as much as they can possibly afford to pursue the most sophisticated components, connectors, sockets, signal and power cables, power supplies and distributors, isolation devices, grounding solutions - basically every technology they can find and afford for every little delta gain they can manage.
This is where the balance shifts.
You see, each percent and a half realism improvement builds on the previous, the collective weight of which can amount to between fifteen to twenty percent overall gain to effect which can be so profound, the entire chain of improvement can no longer be called a ‘diminishing’ return. And while the value of that total return, in truth, can only be determined by each and every one of us independently, those who have actually heard the deep realism that such combined improvement brought will testify to the disbelief and amazement that was felt with the experience.
My sense of it is that our hobby is far too profound to be limited by a phrase which applies more to objects evaluated in isolation than the entirety of relationships that an audio system is.
In friendship - kevin