When an assassin killed Archduke Franz Ferdinand of Austria in 1914, no one called it the start of the First World War. That happened years later, after the implications, consequences and scale of the response could be assessed. It's often the way. That's why historians are important; they put events in context.
Similarly, I doubt anyone knew how our world would change after Steve Jobs and Steve Wozniak built their first computer in Jobs' parents' garage in 1975.