I don't see how this is true. If the question is "what are the real world applications of X in mathematics?", most people would be satisfied by any absurd answe

I don't see how this is true. If the question is "what are the real world applications of X in mathematics?", most people would be satisfied by any absurd answer as long as it's "in the real world", regardless of what biological goals, if any, it supports. It could be that a certain mathematical research allowed us to develop sturdier pencils, and suddenly everybody is satisfied that we are not wasting our money because now it has "real world applications". The human drive to discover and invent new things in math is fundamentally no different than the human drive for doing the same in the fields of technology, arts, etc'. But we perceive anything touchable as good, and anything imaginary as useless, because that's the kind of culture we live in: Making a slightly faster smartphone so that the activity of swiping a finger on a capacitive touch screen to play candy crush now takes 0.7 seconds instead of 0.8 doesn't need any justification, but thinking about math does.