@Brooko you can probably debunk 90% of audiophile "theory" by that measure. Most people don't realise that the "improvements" they're hearing is simply the music playing slightly louder. Even the smallest of volume increases can make music sound more exciting, open up the stage and reveal "hidden" parts of the track "you've never heard before" (because you were listening too softly, or, as in my case, your hearing's not 100%!). Unfortunately knowing this and applying it in practice will cost the industry millions, so it's often brushed off or buried under piles of marketing nonsense (and make no mistake, most of us are susceptible to clever marketing).
At the same time though you have to admit that scientific measurements, in the wrong hands, can also be used nefariously, as is often the case on one particular and seemingly popular website (which I won't name here) that makes a song and dance about noise in amps and dacs that dogs (let alone humans) can't hear.
So yes, measurements are important and useful, "differences" between audio gear can often be explained away by a small nudge of the volume dial in either direction (along with many other factors, placebo included), and even after all that, each of us hears differently and relates (emotionally) to different music in different ways, which also affects our perception of the music - don't even get me started on that tangent...