The US civil war is the most explicit demonstration of this process. Northern industrial capitalists ended the southern agrarian slave economy, increasing market size and generating extreme wealth in the latter half of the 19th century.
There have been war since way before capitalism was invented. Beside war, humans were doing evil things way before capitalism: south america natives torturing kids to extract as many tears as possible from them before killing them, to please the gods, comes to mind, for example.
I'll never understand this fantasy people who hate on capitalism have that the world would be all fine and well if only this one time we did communism [1] right.
[1] or whatever floats your boat
I hold capitalism with a deep fondness, but I think that's largely because my formative years were in better times. For people who've never known any capitalism except for the mess we currently have? It's quite to see how they can think to themselves that anything must better.
as we will soon find out, when AI will become better at Capitalism than us