I believe it is because much of the ideas were already formulated, but the recent advancements in silicon tech, especially GPUs was a huge contributor. Pair th

I believe it is because much of the ideas were already formulated, but the recent advancements in silicon tech, especially GPUs was a huge contributor. Pair that will exceeding amounts of data being collected from/posted by users, you're got a great catalyst for major companies to be interested, which in turn lead to more research and refinement of old ideas.