There aren't too many people on the planet, people move around & leave old 'hoods behind, the population in the U.S.A. had slowed growth considerably until We allowed millions of invaders occupy it.
You could pave the Commiewealth of PA flat, & put every human being on the planet in it with their own 10'×10' room, if We kept it a single floor. And rest of the planet would be human free, go look at a globe or atlas, then think for a moment.
Too many egos on the other hand.....