With regards to electronics, this is largely the case: most of it is transparent, so you can buy whatever suits your other needs best. That be looks, features, objective performance… whatever you like.
As to speakers, that is another matter. Here, preference is obviously also an important subject. And with measurements, you can find out why you prefer certain things, and then can apply that knowledge to find similar or better products to fulfill those preferences best.
I never said to ignore your perception. You should just be aware that some things that you perceive are just constructs made up by your brain from countless clues. They cloud your judgement, and worse, those clues might be different from one moment to another. So they are not reliable. So always caution non controlled listening.
I agree with everything you say, maybe I find it difficult to express what I mean. I've read a lot of threads here where peoples subjective experience instantly is dismissed and they are told to be hallucinating.
My approach will always be to understand that yes, measurements are important because a human opinion is unreliable especially like you say, since it can feel different even just in different days/times in your lifes hearing the same setup.
But I will always start saying hey Im hearing clear differences - repeatedly in extrnsive testing - I will now be curious as to where they come from and try to study the physical facts for evidence of what Im hearing vs oh Im just insane.
I know for example that my dads stereo sounds way better for music than his avr and nobody will ever be able to gaslight me into denying that. Me and him we both noticed it independantly on every avr he had and without expecting bad performance from them.
Now what the reason is - I dont know but I know that it is true so I know there would be a measurable explanation. It could be simply the power, he had very high end speakers and the stereo amp hits 235W into 4 ohm loads , so possibly average avrs just underdrive the speakers. Maybe - the amp being a vintage amp - it could also be just that it has a perceptible coloration of the sound distortion or w/e that we both just happen to enjoy from hearing this amp for so many years of listening to music.
I was positively surprised that most avrs performing poor is also represented in the measurements here. I do think however that what I experienced has more reasons than just DAC performance - I doubt that a 70-80 vs 90-110 sinad is as audible as our avr not bringing it.
To complete the story I dont live there anymore but the last avr my dad got had preouts to tie the stereo in with the rest of the setup and it is until today the best sound setup that I've heard.
Hes using a 2010 pioneer avr and the stereo is a late 80s Onkyo Integra Analog amplifier running German Canton towers. Absolute beast of a sound, if you dare to bring that volume knob anywhere near the 50% mark its like the ceiling comes down.