So unlike what Marxist said central planning actually works best to quickly grow backwards, agrarian even, economies rather than improving advanced economies.
That actually makes perfect sense if you study Marx's core economic theory, the labor theory of value. In that view, all production is about organization of labor, with some attention to the sources of raw materials. There is no discussion at all of the role of innovation, or information, and the theory is focused on a world in stasis, in which the materials, processes and outputs are all well-known, and unchanging.
But progress comes from the creation of new ideas, ways to make new goods, or make old goods with less labor or less, or different, raw materials. An economy organized on communist principles has few mechanisms for encouraging innovation. The Soviet Union made a big deal of identifying and nurturing smart people and giving them the resources to invent new science and technology, but that is perhaps the least important part of the innovation that moves an economy forward. Not that new science and technology isn't hugely important, but the aggregate impact of millions upon millions of small improvements in processes and business models is larger, especially on the general standard of living. So, the Soviet Union was able to stay in shouting distance, more or less, of the United States in terms of technological progress... but was unable to keep the grocery store shelves stocked. That is in the inevitable result of a system that doesn't incentivize and reward small-scale innovation.