When we first came up with this idea of war, we were really just trying to solve a problem. Destroying the other problem solvers gave us more time to devise and implement our own solution. There were other ways to deal with competitors, though. One specific approach is parasitism.
The original problem was to get an apple off the branch off a tree. At first, we used a general process that could be called “adaptation”. When a competitor was introduced, we found we could deal with that competitor using “disruption”. (We could also have simply out-problem-solved the other player.) That is to say that we reduced the complexity of the problem by removing a component. Let’s revisit that decision.
What if, instead of removing the other competitor, we had simply let him get the apple down and then taken it from him? That’s not disruption. We could have also observed his method and used it as a basis for solving our problem, intellectual theft, as it were. Hell, some adaptive little monkey in some place and time in history has probably even devised a way to just steal all the credit and reward for having gotten the apple down, without having done anything to solve the problem.
This approach is not war, although, it is often a reason for war, and it is a strategy that can be made a part of a larger war-making effort.