> Almost since the beginning of agriculture, agrarian societies have experienced food surpluses, and that's what made the cities appear (as in a pre-industrial

> Almost since the beginning of agriculture, agrarian societies have experienced food surpluses, and that's what made the cities appear (as in a pre-industrial society the urban population feeds from the surplus of the countryside). You are confusing an individual-level surplus with society wide one. It is true that a single farmer, with abundance of land, can produce great surplus of food, much more than he or his family is able to consume. However, on a society scale, there was very little surplus overall. In better years, food was quite sufficient for everyone, sure, but in worse years, people starved, especially children, elderly, and the destitute. This is immediately obvious by looking at the population figures. The population growth everywhere was glacially slow by early modern standards, except when a group moved into previously unoccupied territory, or into territory occupied by groups with with worse food production technology. Consider, for example, population growth in colonial America and in early decades of USA to population growth in UK. If UK population grew as fast as New England in years 1600-1800, by 1800 UK would have had something like 500 000 000 people (half a billion) living in it. Such rapid population growth was only possible in New England thanks to abundant land, very little of it has been previously used for cultivation by native Americans. Or look, for example, at the rapid population growth in Africa today. Why hasn’t Africa ballooned to a billion people already in 1800, despite millions of years of head start? Simple: they simply couldn’t sustain populations so high with technologies available to them. Given right circumstances, the population growth and fall are extremely fast on a historical scale, though it is hard to intuitively comprehend for humans due to us living on a single human lifetime scale.