No muggers, homeless and drug addicts on the sidewalk of Chinese cities, but if given a chance, Chinese would like to move to the US for a better pasture.
That's your opinion and maybe true back in 90s. China is not stopping anyone to move to another countries. You can still apply to go to US to study and work. In fact, getting a US visa is way harder than used to. Most of Chinese not leaving China is because language, culture and family factors. I will never go to US as the gun violence and drug abuse just in a crazy level.