Why are digital streaming equipment manufacturers refusing to answer me?

Audio2design, You're right - that's probably what he was talking about, otherwise it doesn't make any sense.  He says "My system uses fiber optic cables. These go all the way to the dac", hoping that optical connection, shielding DAC from electrical noise, makes incoming music always the same.  It is not why it is the same.  Streamed music doesn't come in real time.  It is just plain data that is pre-buffered.  As long as it is the same data in the same format everything depends on the hardware that creates S/Pdif stream/timing (and I assumed he uses different hardware for different providers).  What makes different streaming providers sound the same is the fact that they send data only. Asking them why it sounds the same (with the same hardware and the DAC) is like asking different bookstores why the same book looks the same.

It should sound the same, assuming same internet provider and hardware, same data, same data format, same streaming hardware, same DAC etc.  "Should", because there might be something else that I'm forgetting.

I looked at Toshiba Toslink drivers.  There are some, perhaps older generation, that go only to about 5 Mbit/s, but they have newer drivers that go over 100Mbit/s.  Such Toslink devices should suffer less from the system noise.  Jitter induced by slow transition time and noise at the receiver's (DAC) end would be reduced as well.

As the study of psychoacoustics evolves, it is becoming abundantly clear that A/B tests will become irrelevant. 

@glupson

i have no affiliation or specific knowledge of thyname, or most other folks who post here

but when i think someone is trolling (not thyname, but someone thyname is pointing out):

-- i click their username and then check ’details’... one can then see when they joined, how many posts they have started or responded to since joining
-- one can also see if they posted info on their own system, and/or pictures of their listening room
-- finally, one can click ’marketplace feedback’ on the profile page ... and see what their track record is trading on the a-gon main equipment site - how many transactions over time, how many buys and sells, comments/feedback etc etc -- this is most important, a measure of the member's history, 'realness' and reputation not as a poster, but as a real person buying and selling equipment, with their real identity revealed to those they transact with

trolls often have

-- a very recent join date
-- a very large number of posts since joining (then you click on those posts, they are argumentative or instigating in nature...)
-- no info on their system
-- no track record whatsoever on the marketplace

Some clarifications
1) the fiber optic cable is what carries the signal. This provides even greater isolation than a cat cable, in fact as far as I know perfect isolation
2) the double blind tests included four people not just myself including a dealer who had to admit the lack of any difference

Someone referred to blanket statements not being helpful. I am not making any such statements. I am making a hypothesis, I test it, and I ask the community here to help with additional knowledge. 
My thanks to those who have responded on the topic.

Jdt1, why are a b tests becoming irrelevant? Any of us who have read o toole’s book consider his work to be seminal in helping understand real differences but is there something more recent that suggests a b tests if properly conducted include bias? Thank you.