The historian Bret Devereaux argues that most wars were indeed fought over land, but that fighting over land had already became unprofitable by World War 1, and wars kept happening anyway because people’s intuitions and institutions had not caught up:
As Azar Gat notes in War in Human Civilization (2006), for most of human history, war ‘paid,’ at least for the elites who made decisions. In pre-industrial societies, returns to capital investment were very low. They could – and did – build roads and infrastructure, irrigation systems and the like, but the production multiplier for such investments was fairly low. For antiquity, the Roman Empire probably represents close to the best that could be achieved with such capital investments and one estimate, by Richard Saller, puts the total gains per capita at perhaps 25% over three centuries (a very rough estimate, but focus on the implied scale here; the real number could be 15% or 30%, but it absolutely isn’t 1000% or 100% or even probably 50%).
But returns to violent land acquisition were very, very high. In those same three centuries, the Romans probably increased the productive capacity of their empire by conquest 1,200% (note that’s a comma, not a dot!), going from an Italian empire of perhaps 5,000,000 to a Mediterranean empire in excess of 60,000,000 (and because productivity per capita was so relatively insensitive to infrastructure investments, we can on some level extrapolate production straight out of population here in a way that we couldn’t discussing the modern world). Consequently, the ‘returns to warfare’ – if you won – were much higher than returns to peace. The largest and most prosperous states tended to become the largest and most prosperous states through lots of warfare and they tended to stay that way through even more of it.
This naturally produced a lot of very powerful incentives towards militarism in societies. Indeed, Gat argues (and I agree) that the state itself appears to have emerged as a stage in this competitive-militarism contest where the societies which were best at militarizing itself and coordinating those resources survived and aggregated new resources to themselves in conflict; everyone else could imitate or die (technically ‘or suffer state-extinction’ with most of the actual people being subjugated to the new states and later empires). Those incentives produce exactly the behaviors we see in EU4 and in the early-game of VickyII where the most successful states are the ones that are rapaciously expansionist. And this makes a lot of sense if you think about the really basic energy economy of these societies: nearly all of the energy they are using comes from the land, either in the form of crops grown to feed either humans or animals who then do work with that energy. Of course small amounts of wind and water power were used, but only small amounts.
As Gat notes, the industrial revolution changed this, breaking the agricultural energy economy. Suddenly it was possible, with steam power and machines, to use other kinds of energy (initially, burning coal) to do work (more than just heating things) – for the first time, societies could radically increase the amount of energy they could dispose of without expanding. Consequently – as we’ve seen – returns to infrastructure and other capital development suddenly became much higher. At the same time, these new industrial technologies made warfare much more destructive precisely because the societies doing the warfare now had at their disposal far larger amounts of energy. Industrial processes not only made explosives possible, they also enabled such explosives to be produced in tremendous quantities, creating massive, hyper-destructive armies. Those armies were so destructive, they tended to destroy the sort of now-very-valuable mechanical infrastructure of these new industrial economies; they made the land they acquired less valuable by acquiring it. So even as what we might term ‘returns to capital’ were going wildly up, the costs of war were also increasing, which mean that ‘returns to warfare’ were going down for the first time in history.
It’s not clear exactly where the two lines cross, but it seems abundantly clear that for the most developed economies, this happened sometime before 1914 because it is almost impossible to argue that anything that could have possibly been won in the First World War could have ever – even on the cynical terms of the competitive militarism of the pre-industrial world – been worth the expenditure in blood and treasure.
At the same time, Gat notes that human societies didn’t suddenly reinvent themselves in 1900. We have all of these institutions, these social habits, these values, these works of literature and culture which were produced to help our societies survive in the environment of competitive militarism that existed before 1900. It is hard to stress the magnitude of the shift Gat is talking about here – taking the modern state, the most efficient violence-machine ever developed by humans – and putting it in a world where war is maladaptive is roughly like dropping a polar bear in the Serengeti. Everything that bear has ever learned is suddenly pretty useless or actively harmful. So societies entered this brave new industrial world with a whole lot of habits and institutions designed to push them towards war because war used to be how one profited and survived.
The historian Bret Devereaux argues that most wars were indeed fought over land, but that fighting over land had already became unprofitable by World War 1, and wars kept happening anyway because people’s intuitions and institutions had not caught up:
This is a good point. My year of 1914 was too late. I failed to account for cultural inertia. I have changed the year to 1776.