Except most areas of the Earth are not suitable for human habitation. Humans cannot, or d not want to, live in many areas. Such areas include nearly all of Antarctica, the interiror of Australia, deserts such as the Sahara, and Gobi, and places like Iceland whose national populations is smaller than the Town Of Hempstead.<quoted text>
certain parts of the world are overpopulated like Japan but other places severally underpopulated. Therefore decreasing the number of humans in general isn't necessary, just spread people out more evenly.
People do not, and have never wanted, to spread out evenly. No life form on the planet does that. All life forms occupy niches that are most favorable to their survival and comfort.