"I think more people need to read Sagan's Demon Haunted World. He dedicates a whole chapter on exactly this subject, using an allegory in which the queen ordered Sir Maxwell to stop doing his useless research on electromagenetism but in stead build a device that can transmit pictures over distance... point being of course, that with Maxwell's research into magnetism, there wouldn't be TV, radio, fancy electronic devices, etc.
This is exactly the same thing. Look at what NASA and ESA have given to the world without every thinking about the economic impact: MRI, networking systems, teflon, fancy polymers, etc. None of that would have existed because the research that led to these fruits of science would have deemed unworthy. "
I thought about looking up some more things that were discovered during the pursuit of "useless" knowledge but then realized there are probably way too many.... and I have work to do.