It would only take about a hundred years to drastically reduce the population of the world to ten percent or less of its current level without hurting anybody and suddenly the environmental challenges and available natural resource issues are drastically easier to deal with in a transformative way.
That would require that the whole world cooperatively curtail any desire to have more babies except the limited number that make the math work. Outrageous you say? But still maybe more likely than that most of the world will do away with powered personal transport with some decent cargo capacity. Why would they?