There are some brands of bicycles that can cost more than the down payment on a car. Why? Surely making a bike lightweight and reliable isn’t so difficult that it warrants that price? Is it just the brand name or maybe it has to do with customization options?
Something I haven’t seen mentioned in these threads is economies of scale. Most cars are kind of engineering and machining marvels especially for their price, with a huge amount of their manufacturing being automated to a very high level. Fancy bikes probably do not have the production volume to justify that kind of automation. Their price represents their actual production being less efficient, not being able to amortize the R&D costs over as many units, and general luxury premium.