Most times that a country attacks another is a tragedy of the commons situation. A few people at the top will profit from the war even if most citizens from both countries lose because of it.
The country as its citizens does not profit from war. The country as its leaders sometimes it does, or at least it may do so in the short term.
Which is why the recent wars between Israel and Hezbollah, Iran and Houthis are so paradigm shifting. It's the first time in all of human history that the leaders are the ones to die first. If this is the new status quo due to modern intelligence capabilities and stealth fighters, then you're dealing with a whole different set of incentives.
The first time in recent history, yes. Not sure about the first time in all of human history: human history is long, and often leaders used to lead from the front.
Two states are at war, and their constituent citizens are helping each other despite the war, and you imply that's the manufactured part? Heaven help us, we should all be so lucky if whoever's manufacturing that happens to improve their assembly lines a bit. Maybe they'll manufacture all of us being interested in no wars again, ever.
I think what they refer to is that while the interests of the individual and the country almost never align, the government can work to align these interests; e.g. through tariffs on trading with that other country. By doing so, a country can reduce/remove the incentive to trade with that other country's individuals, thus aligning the interests.
