World war happens all the time. We hurt each other all the time. Sometimes fatally, sometimes not.
When will World War III happen? Is it a valid question? People die every day of so many causes. Mostly because they cannot avoid situations they must live through in order to survive.
Free man from the need to work for a living. Free man from having to do anything. World war is happening all the time and will continue to happen. It doesn't have to be officially declared by nations and people don't have to be killed with guns and bombs for it to be a world war.
Even if people are not killed, people are injured daily. No, not the construction worker. You. Yes, you. Doing whatever is unnatural to the body hurts your health. When you and everyone else have to work for a living, you force your body to act in a certain way, whether it is natural or not. World war happens all the time. And you are an injured soldier.