After 1949,   class struggle had been the main tool and guiding ideology that GCD and Mao used to run China.  However, Class struggle is only good for a destructive revolution but not for construction of a country, from ancient to now.

CR Cultual Revolution was still along the track of Class struggle except redefining a new kind of class enemy, i.e. so-called Capitalist roaders inside the party.  After CR, those Capitalist roaders regained power,  learnt from the bitter experience.  started to give up the theory of class struggle, and opened door to western world.

A new era of China began,  for better or for worse.