That's your idea of a world war 3. Yet there are other scenarios of a world war, which not necessarily combines with a world wide destruction of all infrastructure,
but with local spots of destruction. Even in WW2 there were a lot of countries without or with just a little impact on infrastructure. People there only knew about the war from the media, just like today. We are watching a coalition of nations bombing countries somewhere in the world with civilian victims and we call it "war on terror". We watch suicide bombers killing hundreds of people in Israel, Irak, Syria etc almost every day for decades now. Did we salute these poor souls or did we stop for a moment of silence for them? Hell no! But we are all "Charlie", "Paris" and "New York". What will be our answer? More bombs on civilians I guess, which lead to more suicide bombings of terrorists and so on.
Let's see the definition of "World War" on Wiki:
A world war is a war involving many or most of the world's most powerful and populous countries. World wars span multiple countries on multiple continents, with battles fought in multiple theatres.
Based on this definition, we have a WW3 since September 11 2001, which is still ongoing and our Bitcoin network is still working fine.
You really think nobody will not use nuclear bombs in the war and this war will stay clean..? If only one A Bomb exploded you can expect nuclear winter in whole world. Nobody wants to loose this war for the world, so they will loose it together. You cannot expect for WW3 to be different from WW2 or WW1, it can only become more violent and destructive, the stake i very high!
Your statements are hard to understand and when I try, I find too many false arguments.
1. Why should there be a "nuclear winter in whole world", when only one "A Bomb" was dropped somewhere? That makes no sense.
2. WW1 started with the assassination of one person :
The trigger for the war was the assassination of Archduke Franz Ferdinand of Austria, heir to the throne of Austria-Hungary, by Yugoslav nationalist Gavrilo Princip in Sarajevo on 28 June 1914. This set off a diplomatic crisis when Austria-Hungary delivered an ultimatum to the Kingdom of Serbia,[10][11] and entangled international alliances formed over the previous decades were invoked. Within weeks, the major powers were at war and the conflict soon spread around the world.
I think this situation is not too far from the action after 9/11 and also the situation with IS right now. I think we can call USA, Russia, France and Germany "major powers" which are "at war" right now, so why not simply name this "world wide war on terror involving major powers" WW3?
I think, it is because we fear to let the demons out as soon as we name it.