I was initially rather shock that anyone would buy an meter-long AC cord at over $100 let alone 50x that. That curiosity took me to Dave's video and others... "What kind of nuts are these..." was dominating my thoughts.
But... The value of things is defined by what others are willing to pay to have it.
I am sure in a blind test, one cannot distinguish whether one is wearing the Hope Diamond or one is wearing merely a properly shaped and weighted piece of common rock. So, "fools" are aplenty everywhere you look.
If $5000 for an extension cord buys them satisfaction or happiness, It is not for me to argue.... (If you can peek into my brain, you would see my dominating thought still is: Damn bloody fools, go buy miniature solid gold toilet, it will hold its value better...)