Just an interjection:
Claiming that "supply and demand" justifies the way that cables are currently priced just shows that whoever is making the claim has no idea what they're talking about. Supply and demand, even in its most simplistic form (that many are referring to in this thread), assumes perfect information. Without this background assumption (along with several more, but those other ones are usually fulfilled fairly well), a price equilibrium does not indicate economic efficiency or a proper allocation of goods. In fact, given that knowledge of the market is laughably low (no R&D, no objective information, no government or even voluntary standards organizations... hell, a large number of cables aren't even UL certified) just tossing out the term "supply and demand" means essentially nothing.
Think about it this way: if someone claimed to have the cure for cancer and sold it, the product would likely fetch an extraordinarily high price. However, if the product didn't actually do anything (and people weren't aware of this fact), the price equilibrium would be far from efficient. Even if the product did cure cancer, but had a large number of undesirable side-effects such as organ failure (and people weren't aware of this fact), the price equilibrium would be completely different from its allocation if people were aware of this fact.