Transports are simple to make, just requiring quality components and work. Like any technology, they are becoming commoditized.
DACs are still evolving. Lots of development still going on, competing technologies, advances, improvments, excitement. This is the forumula for high demand. High demand means higher prices.
Add to that the smaller production lots of the high end pieces and the customized nature and you get higher prices.
you order a lampizator (for example), they ask you what options you want, and they build it. You order a transport and you get a mass produced component prepackaged in a retail box.
Jerry