In the past 40 years, the freedoms of Chinese people have exploded. People could not choose what to wear, where to work, what to eat, where to live. Now they can. Millions travel world-wide every year, and all of them return home. Why would they do that if China is as bad as you say?
As for "a revolution against Beijing": prof. Mahbubani says that there are actually hundreds of protests in China every year. But those people aren't protesting against the central government: they're trying to get the central government's attention, to help them with their grievances. The central government is very popular. According to a poll by Harvard, who collected data over a 15 year period through anonymous in-person interviews, support for the central government has increased in this 15 year period. In 2016 (last year of the study), it was at an all-time high: 96% of respondents said they're satisfied or very satisfied with the central government.
What makes you believe you are more right than prof. Mahbubani and Harvard?