If you have no idea what your users might want and no interest in finding out, simply promise investors that you're building an app for everyone that can do everything, and therefore will have everyone in the world as your addressable market (wow!) with the global GDP as potential revenue (wowza!)
the "everything app" is the must-have startup idea of the season for most wildly overrated sociopath dipshits in silicon valley.... if you suck as a human being and have an extremely punchable face you have got to be developing a superapp right now