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

One of those best friends had worked part time a decade+ ago for a major audio high end retailer. He brought home a lot of equipment. He was generally dissatisfied. It is when he met my best friend (Golden Ear and remastering engineer) that he settled on his equipment which consists of a VPI Scout+/arm, Dynavector 20X2 H, McIntosh C20 (2nd version), RAM RM 9, Kyocera 310x and Von Schweikert VR35 export. He was still unhappy with his sound (this is in 2020). I proceeded to suggest changes which he gladly did. These included giving him a Black Synergistic Research power outlet, removing the cheater plug on his amp, replacing the XLO cable with GroverHuffman Empress cabling from 2016 for the CD player, pre-amp to amp and very low capacitance, all silver turntable cabling. He had a good quality turntable power cable and the other equipment have captive power cables. His shelves were wood and set on screw points on his stand. Two wobbled where the pre-amp and CD player stood. He replaced the screws and stuck blu-tack instead (his VPI sat on Aurios and a 2" thick concrete slab).

The result of my and his tinkering with cables, shelving and tweaks was utterly amazing. He is ecstatic with his system and although it is not high-end, it is oh so beautiful to listen to. His speakers permit great imaging and soundstaging nearly 90 degrees seated on side couches. He has excellent deep bass and full dynamic sound. Total current cost of his system is under $15K. (The VR35 export are superior to the VR33, using parts quality from the high end speaker line). He has returned the favor by introducing me to be-bop/post-bop jazz (he has the very expensive LPs) on CDs. My 50s-70s jazz collection has doubled by about 300+ in the past year (I have a sizable early jazz collection as well). Great performances and great sound. He purchased a large collection (55) of Mercury Living Presence classical CDs from hearing my complete collection.

This is where the enjoyment comes in and not in measuring equipment for my friends and myself. Give us some measurements so that we understand the limits and interactions of equipment, then listen for the rest. Cables and tweaks to date, require listening only without adequate (easy and quick) testing.

@westcoastaudiophile I don't know of any high end/expensive/boutique cable manufacturers who provide testing measurements of their cables.  I certainly don't know how the better sounding cables measure.  Similar to my prior occupation as a commercial real estate appraiser (not to be confused with residential appraisers), my exhaustive work involved both science (math, computer models, physical inspections, details, interviews) and art (interpretation of non-physical elements such as location, effects of details on the adjustments such as environmental issues, etc).  I provided reasons for all my adjustments, based on paired sales analysis and judgment calls (based on my experience and interviews).  

So it apparently is with cable manufacturing, a mixture of science and art.   I can't explain it.   I would hope that manufacturers would do a better job of it rather than puffery.  While most explain part of their cable construction, many don't, possibly due to proprietary construction limitations.   Even some of the most expensive cables have virtually no information (MasterBuilt, sound great in systems I've heard but I have no idea why).  

@fleschler +1, the most important measurement= listening satisfaction :)
In LEAN manufacturing they have a saying, what gets measured gets done. The problem is you can measure too much and get lost in the details. This is why I stick with the 80/20 rule. 20% of any system provides 80% of the results. I don't see the value of buying a DAC or a cable that measures so well that only a bat can hear the difference. If you get that 20% right the rest is an adventure toward a moving target which we can only aim at but never hit...perfection. 

@fleschler thanks for reply! I see as on you are measuring cables by price, not electrical performance, and priciest cable does sound better.

@westcoastaudiophile No, I absolutely don’t believe that. After testing 100s of cables, I know for a fact on various systems, that the most expensive cables are often inferior (sounding). High Fidelity cables using large magnets in line is one of the worst examples just based on poor engineering (which I previously described one $1 million system owner who was dissatisfied as was I, until he changed from $105,000 in those cables to $3,500 in cables). I have no idea how the HF cables test/measure and I doubt anyone else does either.

You can view the non-proprietary construction of the GroverHuffman.com cables (older site, could use an update on materials) and his patent. His cables sell for  $300s to $900, not $1000s or $10,000s. He loses potential customers because they don’t have the cachet of expensive, name brand cables. He has more than enough business (handmade) with a world-wide following.

A $35 Chinese made cable is going to cut corners no matter how one looks at it. In the commercial appraisal business one can offer cheap, fast and good quality work but only two, not three. I provided good quality (great quality) as fast as possible. Not cheap.