Nearly all manufacturers do not advertise/exhibit their product measurements? Why?

I have to say that some of the responses by certain posters, including the OP, have been very disappointing.

@prof is a serious audiophile who has related, professional qualifications, is an independent thinker, and a very helpful contributor to a number of audio forums. His contributions are almost invariably substantial, respectful, and grounded in facts. His impressions of certain speakers are as eloquent and useful as any that I have come across from professional reviewers.

It’s a mystery to me why anyone would lash out at him, essentially because he refuses to budge from the reasonable position that if people hear differences between components when there is no scientific explanation for such differences, the claims can only be fully compelling through blind testing.

Note that I am much more of a "subjectivist" than "objectivist", and strongly believe that I have heard differences between both speaker and powers cables. I currently use some fairly expensive cables, albeit purchased used. I have not engaged in blind testing because of how complicated and expensive it would be, but completely agree that @prof would be correct about my claims being suspect. I can’t deny that I am vulnerable to biases, nor can I guarantee that I would pass a blind test.

I also don’t get the vitriol aimed at @amir_asr. I don’t spend much time on his site, but to dismiss his qualifications with the wave of a hand is ludicrous. He has a far better foundation on which to perform the kind of tests that he does than the vast majority of audiophiles.

At some point I will write a post about some of my recent experiences with power cables, which were certainly compelling to me, even in the absence of blind testing!

This is another review of the Nordost Tyr2 cables from TAS that includes the specs:

"So, transparency, precision, purity, depth, texture, openness, expansiveness… Nordost’s Tyr 2 loom brings all of this and more to the listening experience. Yet as I wrap up these thoughts another word now pops to mind that perhaps best sums up my analogy between wine and audio: transformative. That is perhaps the ultimate thing I can say about any experience."

Wayne Garcia 2020

From the beginning of the hi-fi hobby in the 1950s, "performance characteristics" WERE tests results.  Trade magazines used 3rd party labs (Hirsch-Hauck etc.) as independent evaluators.  And for decades my policy was not to buy anything that did not publish meaningful technical specifications that were the minimum performance a buyer could expect.  However these evolved into meaningless "marketing specs" that, if they measured anything, was the lone "creampuff" no one could expect to buy.  Now living in a cancel-culture that poo-poos science and expertise, many (most?) consumers don't have the knowledge or time to learn about measured performance specs, so manufacturers seldom publish them.  Many store salespersons haven't a clue.  One of the last to fall was JBL Professional until acquisition of Harman by Samsung, where established models have been cancelled wholesale, but new lines have no performance data or curves.  And consumer magazine "reviews" are ever more blatantly advertiser-influenced, using the same purple prose as their ads.  I have T&M equipment, and return sub-standard audio electronics, typically for "pin1 problems" or output powerr given as only one channel driven to near destruction.  And rejected speakers for high distortion, flabby bass, and advertising bogus LF extension (rather than -3dB, advertising "range" that implies -10dB).  Caveat emptor - Buyer beware.

@rcaguy +1 I agree with you.  There is a lack of accurate test measurements by manufacturers.  There is an overabundance of purple prose.   Specs are often meaningless (when I see -10db bass frequency, I assume there is something suspect about the bass response).  That is why I started this forum.  I certainly would not want to purchase a cartridge not knowing it's operational characteristics and frequency response, then installing it, breaking it in, adjusting it's installation and find out it is a mismatch physically to my arm or pre-amp or sonically to my taste.  Tweaks and high end cables are the worst with no specs or measurements generally.

@holmz  The Ruby 3 was $3000 in 2005.  Today, if new, probably $4500-$5000.  Out of my price range (although I can afford it, I just can't tolerate owning such a delicate item that could be rendered worthless so easily).  Retailers were trying to convince me that the Umami Red $4000 cartridge would be perfect for me.  Maybe.  I made my choice after hearing many friends Dynavector 20XH and maybe half a dozen used at audio shows.  Never failed to impress me.  

@whipsaw Ask yourself, why is Amir bothering to come to this site?  To lecture us on right and wrong on deciding to purchase equipment?  To advertise the superiority of his knowledge over all of us (not me and certainly not my many friends in the industry, manufacturers, remastering engineers and even another very smart and wealthy electrical engineer).  I hate it when someone tells me that I can't determine gross differences in sound without blind testing. That it is all a bias I have (I don't care one way or the other whether it's new or used equipment, cheap or expensive).  I am a very learned listener and have heard over 1000 audio systems in my life.  If uninterested laymen can hear a difference, how much more so for a trained listener?   

When I was in colleges, 45+ years ago, people had me have their equipment repaired and would install them with the best sounding/matching cabling.  I remember one system with all tube Harmon Kardon gear and large Altec speakers.  I had them purchase a Harmon Kardon turntable, Dynavector cartridge and Fulton speaker cabling.  Boy, that was a nice sounding system.  I'm sure Amir would hate that system after he measured it, it's so full of distortion.  Sure, there wasn't much to set up a cartridge in that table, just VTF and VTA at the time.  Regardless, the elderly and wealthy couple loved it until they passed.  I make people happy listening to music.  I wouldn't trust Amir's opinion on sound, only his test measurements.  

I'm surprised by the number of "data deniers" in this thread, some saying they prefer "just listening to music."  You can do both.  Attending to the technical can only make your enjoyment of the music better.  Such as by eliminating distortion artifacts, especially with analog media, such as vinyl.  (For cartridge & turntable science, note the 2nd edition of "Better Sound from your Phonograph" is out.)