As for those asking what will be the catalyst for such an event: Likely some poor sap of a country becomes the “testing ground” for a new kind of a war, a show

As for those asking what will be the catalyst for such an event: Likely some poor sap of a country becomes the “testing ground” for a new kind of a war, a show of force to other countries that cyber power can be the air power of the 21st century (we will see). Russia invading the Baltic countries (who actually have pretty decent cybersecurity) might be a good example. Or perhaps China invading Nothern Vietnam, where they lost a war in 1979.