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?
Not very expensive. If you buy a bicycle for function (i.e: to ride from A->B), it very cheap.
I think what you are looking at is bicycle for sport. These stuff people want lighter frame, low friction, … and ready to pay more for competitive.
So do many other thing in life. Think watch, a digital watch only show time (dirt cheap) vs apple watch (expensive), vs rolex (veryyyy expensive).
There are always a price and quality for people who ready to pay.