Who makes the best copper cables?

IMO if a cable has continuity/passes a signal it is "good enough." I have been around too long to get excited over wire.

Cables are poison to a good system. Plain and simple. I trust my ears not other peoples opinions. While I never went into forums and ridiculed people that thought other wise, I was never a believer in them either. Then I bought and sold hundreds of pieces of equipment trying to get a sound I liked. It was always good but never as good as what I heard in the shops or at shows. Then a friend sent me a usb cable to try and it opened my eyes. Next step was auditioning cables. My mindset what what cables are adding better goodies to the sound. Then I received project v1 to audition and realized that all these other cables, while good, the good qualities they had were merely just imperfections. The v1 opened up a window. No constrictions. However, like I said I’m a cable dork and acknowledge there might still be even better.  I mention all of this because I had a $22k brand new first in the. US esoteric n01xd se and arc ls28se. I thought just going big on my dac would be what I needed. It was nice. But when I got the cabling I sold all of my electronics and went to work on good cabling, conditioning/grounding,  fixing my network. Now, my base is so good that even when I have just my 8 year old denon home theater receiver plugged into my network and streaming qobuz, I have more detail, insight and stability than I ever had with the expensive electronics. In fact aside from the separation of instruments and natural timbres, my system sounds better than pretty much 99% of what I hear at shops and shows. Even a cheap but good cheaper dac and a nice tube pre should be all I need to have a system that I will finally enjoy

Another question is:

What advantage is a 'superior' cable going to have over the ones the recording studios used?

OP, 

Thank you for sharing your journey. Sounds like quite the whirlwind. May I suggest Robert Harley's book: "The Complete Guide to High End Audio" to help put your experience in a framework. I think you'll find it fascinating and educational.