General Electrics’s GE9X, the engine powering the Boeing 777X, under construction.In my recent article contrasting Chinese dynamism with American sloth, I described how the Chinese state-capitalist system has an unusual tolerance for social disruption, which, when paired with prescient leadership, enables massive societal uplift. Many of the comments, however, extrapolated this observation about state capacity into prophecies of inevitable American decline that I did not intend to imply. Perhaps...