I have no way of verifying this rather astounding claim, but perhaps someone else does:
Virtually no high end cable company makes its own cables. Some don't even design their cables. Most of the cables come from the same factories; they choose among the factory's options of colors, materials, designs, termination styles and length. They are quoted a price and that's it. Some may do custom terminations, but that's all the "manufacturing" they do.
See http://www.high-endaudio.com/magaz.html#Cab
This is a question of fact, not subjectivity. Saying "But I can hear the difference" is irrelevant. Can anyone convincingly verify or debunk this claim?