The controlled market lacks economic vitality: Lacks competition, freely-explorative tech innovation.

Over-dependent on the wisdom of the heads( The Soviet Union had a centrally planned economy in which the state controlled all economic activities, including production, distribution, and pricing decisions. Central planners lack accurate information about consumer demand.), leading to some undesired investments. Lot of money, resources, and productivity is serious wasted. In contrast, capitalism-based countries can seek ideal through the proof of market.

Investing too much on heavy industry project, like space race (Wanting to strengthen people's belief of national pride and collective development to bring higher productivity. But belittled the importance of light industry and people's life quality.

Economic productivity is over-reliant on faith of communism. Due to the absence of private ownership, individual companies becomes production unit or tools.

Some USSR countries choose to be independent because they can economically support themselves.

The Soviet Union's integration into the global economy was limited, and its trade relations were largely confined to the Eastern Bloc and a few other countries. This isolation prevented the Soviet Union from benefiting from international trade, technological advances, and access to global markets.

Pressure from better wealth and life quality in capitalist countries.