After having put in a lot of effort into their research and dissertation, it is common for PhD students to seek pragmatic justification for your research. I think and propagate that it is a mistake that often leads to nothing but a lot if dissatisfaction from the work. Instead, I would suggest that the work should be looked upon as an intellectual exercise which may not have any immediate value but surely some subsidiary effects that can be valuable.
I can may be compare a doctoral research to a game of cricket. Many of us may find absolutely no pragmatic justification in spending all your youth in perfecting the skill of hitting a ball with a bat and catching. It just, maybe sounds absurd and may demotivate the players if they start thinking on those lines. Still, cricket does have its own value and many subsidiary values related to physical exercise, stamina building, and reflex actions and so on. It becomes more valuable when it inculcates the emotional strength and traits such as team spirit, pride, joy, frustration and other emotions in the players. It indeed is a valuable sport and likewise a PhD research is a great intellectual simulation which makes good use of the logical thinking, problem solving and constructive argument traits of a researcher. With this opinion, does it really matter what is the subject matter of your research similar to what is your cricket gear made up of? When your research is absorbed by others. I may appear that they have not picked up anything of immediate value but it surely does act as a stimulant and may produce such worthy side effects for you as a researcher and for the others who consume your research in different capacities.