I just looked at some of the other listings. The non-custom work units are actually quite reasonable. I suspect they simply don't want to give away their labor on plinth building, etc., plus the listings serve to draw attention to their business as a whole so they price them for very motivated buyers.
I hope they are doing well.
I first noticed them for their listing of a Sonic Frontiers SFD-2 MKII DAC which they have priced at about a third more than usual price.