But we would not then be able to safely handle sanitation, transportation, air pollution, etc. Nor would we be able to handle the logistic required to feed everyone in such a scenario.
"Hypothetically, if we were to jam every human on earth into a space the size of Texas; it would just have the same pop. density as Manhattan" is not remotely the same as "in practice, all of humanity could comfortably live in a space the size of Texas with the density of Manhattan."
"Hypothetically, if we were to jam every human on earth into a space the size of Texas; it would just have the same pop. density as Manhattan" is not remotely the same as "in practice, all of humanity could comfortably live in a space the size of Texas with the density of Manhattan."