China was a manufacturing powerhouse 25 years ago. Not quite as much as now, but even in the 1990s they were clearly a powerhouse. They have done more automation, but they have been a powerhouse since the 1990s.
Things really picked up for China with Deng Xiaoping in the 1980s. When people say America can't do X like China can, they don't mean it will take a lot of time, they just mean that we don't have the will to do it. And given the huge environmental costs China incurred in its rapid development, they might be right.