Because it's a massive program that required several technologies that were never used in production aircraft be made production ready with expensive state of the art technology and deliver a result that has acceptable performance for a wide range of users with a wide range of use cases.
It was pretty obvious from day 1 that this would be expensive af.
There’s nobody more cutting edge than NASA, and its budget _since inception_ is still less than this. There’s expensive and then there’s wiping my ass with hundred dollar bills expensive.
