And this is a bait and switch: you were talking about the propensity of countries or people to go to war, now you are talking about the scale of destruction.

Cities were routinely razed and famines and disease killed scores of people in historical warfare as well - we have the accounts, we know it happened. The "difficulty" of implementing any of this was enormous given the lack of modern logistics or simple things like refrigeration to keep armies resupplied.

How does this support your argument though? World War 1 increased the level of danger and destruction of warfare and...then we had World War 2. If the hypothesis was that making war easy leads to more wars, then no example presented shows that because WW1 was at the time the most destructive war in history and simply set the stage for an even more destructive war.