Well, first of all, they had two thousand years autocratic Imperial rule. This was overthrown in 1912, but then came the Japanese invasion, then WW2, then a civil war.
The civil war ended up being won by a somewhat anti-intellectual group of people (the Communists) who had all sort of economic backwards programs (not to mention social upheaval by sending intellectuals to "re-education" camps).
As for the reason why things remained static during the Imperial rule: this was actually the norm for most civilizations. If you look the world in 1600, just before the invention of the telescope, Western Europe, the Ottoman's, the Mughals ruling in India, and Imperial China, weren't too different. The non-Europeans were actually ahead of the Europeans by some metrics.
Once the Scientific Revolution was embraced by the Europeans, and generally rejected by everyone else, the Euros left everyone else in the dust. The real question is: why were the Europeans the only ones to embrace it.
The book Intellectual Curiosity and the Scientific Revolution by Toby Huff explores this question. Highly recommended.