I have a few questions / observations that I think are relevant to this subject.
The first is what makes a cable "worth the money". Well that's perhaps surprisingly the easiest question even if there are a few answers...
Purchaser perception: It's worth it if the customer still thinks it's worth it after they bought it - trite but true.
Relative perceived Quality: If the customer perceives the subjective ratio of quality to price to be equal to or greater than competing products.
Quality for price: Best perceived quality achievable in a given price bracket.
Price for quality: Best achievable price for a given perceived quality.
However these all depend the price element and also on some (subjective) measure of perceived quality...
Can we define "perceived quality"?
Well possibly we could achieve an estimate of mean perceived quality using double blind testing, but of how much use is this when were's talking about a stimulus (such as music) that is perceived differently by different individuals, and additionally subject to the whims of individual taste. Certainty the mean perception of quality could be used as a guide for selection of a short-list for personal assessment, but, due to the individual response to the stimulus, it's not an appropriate decision making criterion.
Finally we come to the price element; and here we at least have the potential for a little more clarity as there are a defined number of specific criteria...
Per item materials cost
Per item manufacturing cost
Per item testing cost
Per item marketing cost
Per item packaging and distribution cost
Amortised product development cost
Amortised production set-up cost
Per item sales cost & profit (distributor & retail mark-ups)
Unfortunately there's very little information from high end cable manufacturers to justify the costs. However, having made many of my own cables, I do have an understanding of how cables are constructed and the materials in use. Hence I have a reference point from which to make comparisons with commercially manufactured cables; including how to estimate how much is engineering and how much is bling.
So, working from this position of somewhat above average knowledge, my conclusion is that, in the case of expensive cables, sadly the last two seem items to be a much greater proportion of the overall cost than is the case for most other products.