most socialist systems participated in the capitalist economic system. The USSR, for example, attempted to create the capitalist mode of production that was almost entirely lacking when the revolution overthrew the czarist regime. They had to, according to their marxist theories, in order to develop a proletariat with a revolutionary consciousness. Similarly China was faced with an economic system that was the shambles left over from the long degeneration and colonial exploitation of the ancient regime, and proceeded to attempt to build a modern capitalist economy under the control of the party, as the USSR was doing. In both the USSR (except for the brief period of the NEP) and the initial attempt during Mao's lifetime, the market exchange was not used to set prices or drive production and planning, but instead top down '5 year plans' were used. They didn't work well, why is a complicated discussion, they actually might work a lot better now using the vast compute, information and communication tech available. The USSR under Gorbachev attempted to reform both their political and economic systems and collapsed. China looked at that and reformed their economic system, allowing much of the economy to be market based rather than planned, while keeping political control under the party. Their reform has been spectacularly successful in modernizing their economy, so successful that the USA at this point is determined to sabotage their system and, if necessary, destroy them militarily rather than allow them to dominate the global system.