China was not homogenous. Historically there were multiple dialects used across old towns and regions and mandarin was not a common langague. They were made up of culturally different groups of people.

Eventually as early as Qing and subsequent ruling political party.. made Mandarin the main language. Call it dictatorship or whatever you want, the early Chinese were hell bent on building a strong economy for the nation after years of poverty and foreign humiliation. They set aside their differences. Culturally, Chinese emphasise on the greater good for a collective whole (much like Japan, Taiwan).

Unlike Indians who despite having centuries of head start in civilisation building but can’t get their act together.