China overproduced STEM grads so that their industries could hire them for pennies on the dollar. They had to withstand insane competition starting in elementary school, only to end up unemployed or doordashing.
This isn’t a PRC specific thing either, TSMC is infamous for having PhDs doing night shift lab tech work for pennies (comparatively).
I don't know why people keep bringing this up as though it is surprising.
In almost any field other than AI PhDs are underpaid on average.
There are many, many bio PhDs working as lab technicians.
Engineers from Taiwan go to mainland China these days to earn more money. Taiwan was pretty brutal with personal sacrifice in its development as much or if more than the mainland. We could say similar about Korea, Japan, and Singapore as well. This is why Asia seems to be taking over the world now, but the people are about as happy as you’d expect.