> why is cheating endemic in China whereas you don't hear the same complaints about people in Taiwan, Hong Kong, Singapore;

Because cheating is a cultural rather than ethnical thing.

There are ethnical Chinese people in those regions you listed, but sure mainland China sailed a totally different cultural course over the last 70 years.

In mainland china, cheating mostly happen because of over competition. If you don't cheat, others will and will crush you in business or academic competition. Cheaters go home for chicken dinner while non-cheaters goes to jail.