Update in the news today. Two related stories.
First, a group of young volunteers are combing the streets, looking for stolen bikes, and then returning them. Some are even locked with cable locks and chains, but the volunteers carry large bold croppers to cut the chains.
Second, police have apparently jailed 3 people for stealing these bikes. I think one person got 11 days and the other person 5 days.

Our school does not focus on not so good students from rich families.

Yes, but it also depends on suitable systems and policies, at both the national, local and school levels. At school level it also applies to the policies within both public and private sector schools, and is also true for special programs.

I currently work in a program, where for the first 2/3 of Gao Yi, we spend 80% of our time managing 10% of the students, most of whom are not usually there in Gao Er; and these kids are not disadvantaged, they are just dis[insert adjective here].

Of course its not a flat table. Stop being so bloody PC. Social mobility is a relevant social goal.

No child left behind is not about the competitive society. Many of the 20% of under achievers are not disadvantaged by social background, many have lower intelligence, or really don't care.
The 20% who could achieve a lot more includes many of the smart kids who are socially disadvantaged, but the crap schools in the poor neighborhoods lack the resources for them to excel. When they do get more money, they have to spend it on under achievers. Helping students who would otherwise get an E, to get a D is not going to change their life prospects. Helping the smart kids from disadvantaged backgrounds to achieve their full potential is going to change lives.

This is the more bold face of gentrification. Looking at the pattern in other cities, the next step, in a year or so, will be to close the wet market as well. A sad but inevitable part of progress.