The manufacturing process of the Rockport enclosures are pretty insane compared to many and if you're not familiar with their design, research it.
Although at this upper end, there are many which are impressive for sure (engineering/manufacturing). Whether or not that equates six figure prices isn't my point, just that these aren't some MDF boxes slapped together. Also I believe they now manufacture their own drivers (not 100% sure though). Not many that do (Dynaudio, Focal etc..), which just adds to the overall R+D costs.