I was born in a city ranked 45th in China by population (from wikipedia). K-12 is 100%. My grandpa lives in a very small village with annual income just a few thousand dollars, K-12 is also 100%. My close cousins come from the same small village, now bank staffs and doctors.
I have friends who's family so poor that the roof got torn away by a typhoon. And I have friends whose parents are simply peasants.
My friend group is definitely biased since I graduated from one of the top universities, but they are selected by exams, so many families are actually not wealthy. In China money usually cannot help you directly on exams, people need to study hard.
Hmm, another thing I'm curious is that what gives the original post the impression that "Chinese people are uneducated". That's a rare heard haha.