I can agree DBT has more value than purely subjective listening. From what I understand, even highly engineering focused companies listen to their gear once before making 1000 units. However, an engineering focused company is going to put the most weight in performance measurements, and I think once you do that enough, you can figure out which measurements yield which listening results, assuming your room is very well treated and your tests are very controlled, your engineering staff know what they are doing and really care about performance (e.g. you keep marketers out of the design process).
I taught myself a lot about room acoustics to get my room to really perform and sound absolute life-like. It took many iterations and hundreds of hours of my time, and thousands of dollars. However, I will admit the same speakers sound many times better than when I first hooked them to my AVR in an untreated room. I also made other changes along the way such as actively tri-amping all 5 channels, adding multiple subs, and a bunch of other stuff. I measured after each change, and this gave me very valuable insight after each change. After a while, I could see the value each change made towards my goal of having the best possible performance at the main listening position (i.e. ultra low distortion as measured acoustically, very nice waterfall plots with fast LF decay times, very nice ETC plot, etc...).
That said, my point is if I were blindfolded and went back in time somehow before I learned what I know now, I would honestly think they were different speakers, and I just might have blamed the speakers. This obviously isn't an ideal DBT as you'd want controlled conditions and to make one change at a time, but I think there is far more value in understanding the science and engineering involved, then learning to measure things and trusting what the results tell you. DBT could easily make a person blame something that isn't really the weakest link in a system based on what they think they hear or even based on their mood on a given day, etc... Psychoacoustics is going to always apply when you are using listening as a metric, and our brains are too easily fooled.
I do agree DBT could be used to show what might not affect normal performance (i.e. audio jewelry, $1000 cables, etc...), but what is the point when acoustical measurements can be made with a $90 USB mic. Can simple REW measurements expose audio snake oil? Definitely, and it is 100% repeatable with very little effort and uses free software. DBT just seems like a waste of effort (and likely to fail if not done right) versus having someone who knows how to measure and test things objectively. I know there are very few dealers that do this, but objectively measuring and then showing what a user should improve next to get the best bang for the buck should be what an end user demands before they drop another $5-10k (but it seldom is for some reason). Do I blame a dealer for selling someone like that a $500 power cord instead of visiting their room? Yes, but I also have to blame the customer a little for not seeking real technical advice or learning on their own.
To reiterate, I guess I really don't see much practical value in DBT either if that's all you are going to do, and it's not like Guttenburg is going to learn enough to do proper measurements and purchase $27k or more in test equipment so there you have it. He may know how to do acoustic measurements, but that's just going to mainly tell a reader how his room is which won't help a reader much with how a piece of gear will be in their room. Again, I think this leaves electrical testing, which can and should be the main focus of any serious audio review though.
Yes but there is that tiny possibility that conventional measurements, in certain cases, under certain circumstances, may be missing something that is audible. DBT still has value if for nothing else but to prove the science.
Guttenberg is one of the worst of believers and deserves to be shown delusional.