Indeed it is the same for other components like headphones, dacs, amplifiers. If people has the skill, resources and time to build these, they probably save a bundle. And for those who can't will just simply buy from the market. Who knows that one day you may just build your own cables with value proposition and setup a successful business for it like in the case of Charleston cable, Entreq, and many other success stories. Bear in mind that this hobby is a niche market so a business may need to have higher-priced products to cover the cost or loss of the other products.
One can also choose to buy from the used market, and strike a bargain by paying a fraction of the selling price as long as one does not fixate on a particular cable and willing to try alternate brand or model.
Sometimes people willing to spend more money on cables due to power of brand. If a certain cable or brand has a lot of positive reviews, people are willing to pay more for the assurance that they are getting a better value because they believe that it is a lesser risk for them after all there is a saying that "Nobody ever got fired for choosing IBM".
It really hard to tell if cables are worth the money because many factors come into play. Factors such as brand-consciousness, feeling good, status, personal perception, customer loyalty, prior experience, curiosity etc. Moreover different people place different value and belief for this hobby.