Some of us live in spread out communities or rural areas. You don’t expect all humans to live in a 2x2 ft cube in a 30 story tall building do you? Also, I guarantee not everyone else wants to live right next to other humans. I try to get as far as possible so I can do anything I want (be loud, be outside at any time, have parties etc). There is actually enough livable land on the planet for every single human to have 2 acres worth. Now, should people have children when there is already billions of us, that’s another question.