People and development go together. The more people you have, the more development you can have. India is experiencing a similar early growth trajectory (from a GDP and energy use perspective), because like China, they have over a billion people. Comparatively, the US for example, has a few hundred million people.
Historically, this has always been the case. China and India were the most populated places and biggest economies for much of the past several millennia
What held China and India back the past few centuries? The west, through its Opium wars and colonialism. Globalization accelerated a reversion to the mean
The takeaway here shouldn't be to end democracy and turn to state capitalism or mercantilism. For the US to keep up, it will need more people. Or AGI I guess