In the bad old days, when somebody had a resource you wanted, you killed them and took it.

But we finally realized that it was a lot more economically efficient to just trade for it. You didn't throw away blood and treasure that could be better dedicated to actually producing something. Plus we fought two of those 19th-century-style wars in the 20th, and it was clear how insanely dangerous modern weaponry had made that.

The greed never decreased, but we became smarter about it. Or at least, we had. Now we're back to the 19th century habit of making it about our national egos as well as resources, and we're willing to throw away lives again for our egos.