Please tell us who is conducting these blind tests, especially those offering prize money. Please also tell us the details of the blind tests you have conducted yourself.You'd have to be hiding under a rock or willfully avoiding them not to have seen them, after decades.
https://www.audiosciencereview.com/forum/index.php?threads/catalogue-of-blind-tests.8675/
I've blind-tested all my amps and did so with cables until I stopped buying anything fancy (but not DACs, I really should get to that). I was unsurprised to hear no difference in the old expensive cables I own (Cardas and..Opus, I think it was?) and anything else I could find. That was a long time ago and I never looked back, given that the third party evidence is just..monumental. There's a great test in that thread where the listeners prefer a coat hanger, and another where they can't distinguish a rube goldberg connector made of very thin transformer wire, a paper clip, and some alligator clips. Cables are pretty easy with level-matching, obviously, but the time between swaps can be pretty hard on audible memory. If you are willing to live with hi-res digital files using each cable, go on over to Archimago's site and take a trial yourself with rapid A/B.
Amps were really a shock for me. I swore I heard differences sighted but utterly failed to get it right blind (Adcom, VTL, Bryston, March Audio). Just used a hand-held db meter for level matching, marked off the pre-amp settings and had my son swap the amps. I was imagining the difference, apparently.
Since then, I've offered $10k to charity to pass blind tests in a properly set up trial. The initially interested always stomped off in a huff over the terms (I initially got Amir over at ASR and Archimago to agree to help set up the trials, and they and many others offered to chip in, you can see the details over at ASR, but that limits us to two places in the world). Of course James Randi famously offered a lot more money.
It's worth doing this for yourself. I still think there could be minor differences that show up in rapid A/B testing, but claims of "night and day" differences in the chain prior to the loudspeakers really don't have an evidentiary leg to stand on. Sad, as an equipment enthusiast, but the truth often is.