No Hi -Fi company makes it's own cables.
Cable making is big, dirty industrial work. You cant run a cable maker without having to run several KM of wire at a time so that £500 a meter cable ain't costing anywhere near 10p a meter to make in the first place.
I would speculate that 99.99% of all wire that goes into Hi-Fi cables was originally specced for Boeing or CAT scanners at next to £nothing a meter.
All you need is a reasonable (thicker than bell-wire) gauge, reasonable quality copper and keep it as short as you can.