Joseph Needham is over rated and did not really understood China, just better than others, and the Needham question is simply human nature. People will go do things that make them powerful, rich, and have a good life. Since bretton woods II, when the USD is not pegged to gold anymore, most US elites will go into law(government officials), finance(rich), medical(rich) and away from STEM. For China, before the imperial examination, there are elites doing science in the han dynasty. After imperial examination, all smart chinese are learning Confucianism classics. This is simply human nature, and so if Joseph Needham know China better, he would not have asked the Needham question.