I believe the class struggle that you are suggesting is not so clear-cut here in China. Most Chinese I know work in the city and have their parents in the country-side. So, the "middle-class" that we normally talk about is the sons and daughters, and the "peasants" are their parents. They are not going to revolt among each other.

Their situation improved hugely from what it was 20 or 30 years ago. They went through hell during all these decades, so they built up such resilience that I don't think that they will revolt simply because they cannot get a job right now.

Also, the Cultural Revolution is still fresh on people's memory (even though no one talks about it). That was a "class-struggle" revolution (supposedly), and I don't think they would want to get back to that time, even if the gap between rich and poor keeps widening.