Telling musicians to evaluate and choose their instruments in a “scientific” way?

I still get the shakes when I recall musical instruments I played at stores that were oh-so-wonderful but just a little north of my wallet's comfort zone. Science be damned.

Perfectly stated tommylion.  I'm one of those loons that like to listen with my ears. 

+1 OP
It’s been empirically demonstrated countless times but deaf ears and closed minds cannot comprehend that basic statistics and common sense say otherwise. People are increasingly scrupulous about performance the more $ they invest, it’s not an automatic placebo. When they claim what we hear is stepping over the common sense line.  I highly suspect either their systems are not transparent enough, their hearing is not as acute, or their conclusions are colored by their expectations.

But, as always they’ll never go away. Best to ignore and focus on good things like music.

I was talking to my one of my musician family members about her issues with live sound.  Most of them were cleared up after proper placement of mic with respect to speakers so as not to induce feedback.  You would be surprised how many people w/o a physics background struggle with these things.  She being a lifelong educator and artist and all.  I then suggested she not use a guitar amp for her miked saxaphone.  The conversation ended.

I’ve wondered how the people over at ASR & audioholics audition gear? W a oscilloscope and calculator?

As far as musical instruments go, my friends late mother was a child prodigy/concert pianist. When she turned 21, she was given a new pre war Steinway Grand Piano. When talking to my friend about audio gear, he raised the issue of how the instrument, which was left pretty much unused after her passing, had deteriorated sonically. It is now with a friend of his, an opera singer, so it can be used regularly and be brought back to life. 
He was asking about speaker and them aging and getting better over time. Given that composites are used for the bulk of speakers, this isn’t really a thing.

I bought a wooden field camera years ago made out of ebony with titanium hardware to try to reduce the weight. They used wood that had been stored at a constant humidity and allowed to settle for years before being used. This to give it as much stability as possible before milling down.

I would be curious to see how aging effects the resonance of plywood. Certainly it will dry out and harden over time, potentially becoming brittle pending climate conditions. 
Instruments require resonance to work properly. Speakers, for the most part, avoid resonances.