I understood The Great Divergence as meaning there are large performance gains, but only for certain people, who are better at resisting distractions brought on by new technology. But my conclusion is closer to there being large performance gains but only for a tiny minority of tasks that happen to really benefit from them and more modest gains otherwise. E.g., smart phones are a great technical achievement, but they’re not a huge improvement most of the time—we already had laptops for most portable productivity needs.