Dynaryder....you are so brainwashed....Bicycle companies must love you lol I bet building frame myself will cost several k in materials, and add couple hundred per hour to build....yup...you have a point...
Quick lesson from me - an economist and life long business owner - If there are people willing to pay outranges prices, they will keep selling it. They are charging that much because they can, not because they have to.
As for fragile high end bikes, its all for weight saving over anything else. I bet you never heard about carbon braking and all the recalls in the last years...that would explain why you are in the dark.