Because they can!! If the real breakdown of cost is analyzed I would not be surprised if it cost under $3,000 to purchase the components and assemble. If they are business people. Seas and the like sell a lot of components to companies that market $15k speakers.
Did I Expect too much?
I purchased a pair of speakers from a US manufacturer who I shall not name. The speakers are beautiful and the sound exceeds my expectations (after a minor upgrade). So why would such a reputable company use six dollar binding posts? It makes no sense. I replaced them with Cardas binding posts and decent 12 gauge wire between the driver and posts. My system is valued for clarity and clean highs. The difference was audible. I know, snake oil. But it wasn’t. I don’t think that spending $15K for speakers is nothing. So yes, I was disappointed.