How wrong you are. The best thing to do with the billions of humans is to pack them tightly in cities. Toward the city you provide fuel, electricity, food, merchandise, and money. Out from the city you get smoke, garbage, pee and poop.
Meanwhile, with all the humans packed in the cities, the rural areas can revert to more natural conditions. Trees and grasslands thrive where there used to be humans. Farms exist and thrive where needed to support the cities. Since cities do not want industry anymore, those locate out to the hinterlands, but that is ok too.
Last thing you want to do is spread the humans all over the place. They do much less damage if you keep them packed in tight in a small area.
Decades ago I did quick calc for # of humans alive then... probably a billion or two less than now.
Anyway, I figured if we all stood shoulder to shoulder and belly to butt with nose touching back of head that all civilization could fit on the state of Massachusetts - with plenty room to spare!