That's a very dangerous line of thinking. Before WW1 the same argument was made because the world was supposed to be too connected by trade.
One can say that nuclear weapons have been the biggest peacemaker known to man. It's hard to imagine another World War since the advent of such weapons. Furthermore, the nuclear weapons today wield a power that cannot even be compared to the ones that were dropped on Nagasaki and Hiroshima. I don't think any superpower today wants another global war knowing that it would spell total annihilation for all those involved.
We also shouldn't discount that the world today has so much more globalization. Just about every country has become interdependent on each other.
Countries cannot profit by war perhaps but that won;t prevent wars. I don't think most wars are entered as the result of a cold economic calculation. They are caused by ancient programs written into our DNA before humans even evolved. So for the time being war is disincentivized by economics but I am confident we will eventually find reasons for a big war anyway
"For the first time ever, fewer people die today from human violence than from traffic accidents, obesity or even suicide."
I don't think many hunter gatherers died of traffic accidents or obesity.
The author of this article is both dishonest and hopelessly naive. He's redefined war to mean "conquest" and "winning" to mean "come out ahead financially", which isn't always or even usually the point of war.
And even if it was he's still wrong. Land itself has value, and with sufficient brutality you can still "win". The fact that we haven't seen a war like that since 1945 in the developed world doesn't mean it's not going to happen again. Hitler planned to basically kill everyone to the east of Germany and replace them with Germans. That would have been "winning" by any definition of the word.