@irenetherogue @implementcontrols not trying to be sarcastic, but it can, as you say, work for billions, if you just care a little less about suffering and death (of others). If you have a million city, how do you feed it? If you have millions of rural settlers like in the early colonization of the US, how do you give them proper medical care, or to ensure that they don't die in an event like the dust bowl?