Why did China's reform start from the economic field?

The Third Plenary Session of the Eleventh Central Committee decided not to take class struggle as the key link, but to shift the focus of work to economic construction, so the reform began with the economy. At that time, after the Cultural Revolution, China's economy was actually on the verge of collapse, with a serious fiscal deficit. There has been a certain ruling crisis and trust crisis in China. The reform should start with the economy and turn the planned economy into a market economy. Moreover, the economic base affects the superstructure, so political reform must start with the economic field.