Nobody realized "the system" had this side effect before it was started, and once the button was pressed, it was pressed...
As your quote says. "economic relationships can decrease the likelihood that states will engage in war".
https://smile.amazon.com/Guns-August-Pulitzer-Prize-Winning-...
Not quite parallel, but IIRC it emerged afterwards that the Soviets had no non-nuclear battle plans for Germany. While the US planners kept two sets ready.
Or that's the picture Tuchman paints.
Not just on the German side, BTW, but everywhere.
Now, this is just a popular history book I recall from memory several decades ago, and the questions you ask sound very relevant!
Right after the quote, the article's authors say that these claims [about Europe being economically interdependent before WW1] are exaggerated and this do not disprove the theory that interdependence prevents war.
You can't point at severity as an argument against a mechanism to control likeliness.
[1] - https://www.washingtonpost.com/news/monkey-cage/wp/2014/04/0...
"Political scientists often argue that international economic relationships can decrease the likelihood that states will engage in war. Nations that might otherwise be inclined to fight can be deterred, informed or transformed by economic interdependence.
World War I has been called the “Achilles Heel” of such theories. In the decades before the war, Europe experienced unprecedented growth in international economic interdependence, both through trade and capital flows. Yet war not only broke out, but the scale of its destruction was unprecedented. Economic liberalism went into retreat. How could anyone sustain the notion that trade could prevent war when the most destructive war in history had followed an era of expansive international trade? For decades, scholars and policymakers alike pointed to World War I as providing strong evidence against the liberal case."