The assassination of Archduke Ferdinand might have been the spark that caught the fire that started WWI but there wasn't a single cause. It was all the back-room alliances between nations that was the kindling that spark caught, and a long build up of new weapons no one had put into total mobilization yet, and a bunch of other things.
If Archduke Ferdinand wasn't assassinated WWI might still have happened. Though history will never know.
Oh for sure, enough kindling has definitely been set down to start a new world war. Adding all the sparks people are making and it seems like history might repeat itself. The next world war might have even started as far as historians will be concerned. I just think that if full mobilization actually happens the prepers are as screwed as the rest of us. The only way to actually survive that with a fragment of our old ways in tact is to already be rich and powerful, should the worst happen.