There is never going to be a time when Earth is perfect and there are no problems anywhere. There is an argument to be made that we should prioritize nonhuman spaceflight but unfortunately robotic missions are not capable of doing a lot of the stuff people can. eg. anything requiring that decisions be made rapidly without the need for mission control to puppet the instruments from Earth. Manned spaceflight also forces the development of technologies like life support, hydroponics, advanced materials science research and the like that would be useful here on Earth as well as medical advances that can be useful for treating osteoporosis, muscle wasting and eye diseases like glaucoma which is the leading cause of blindness. Much of this cant easily be done on Earth due to the need for a microgravity environment. And again, you cant do this with just robots. People have to be exposed to these environments to result in the physiological changes that microgravity causes.