Why must the planned economy system withdraw from the historical stage?

Because the market has the function of self-regulation, the best economic development model is based on the market, supplemented by planning, but this is the market economic system, only the state intervenes more in the economy; The planned economy system was the development model of China before the reform and opening up, and so was the Soviet Union. From the fact that these two countries were later forced to change their economic systems, we can know why the planned economy was finally eliminated by history.