Are manufacturer AC cables good enough?

Misconception #3 is nonsense audio components don't have perspectives but anyway why 6 feet? Suppose your magic cable is 12 feet does the amps perspective change? Lets make the cable 30 feet and connect to the panel box what's the perspective of the amp now, does it know a breaker and bus bar is now the bottleneck? What's the perspective of the wires after the power supply? Complete idioticy.

thyname

... In the meantime not one credible explanation has emerged as to why the last 2 metres of electrical cabling should matter exponentially more than the previous possible kilometres.

Logical fallacy alert, straw man argument. I don't recall anyone here claiming exponential improvement.

Good catch! That was a close one! 

It would be pretty weird for someone who designs hi end power cords to argue that power cords don’t matter. Yes, no, maybe? Answer at 11.

True, they may know they don't matter but they aren't going to come out and shoot themselves in the foot by admitting it.