Answer:
Essentially, there is no competition in a communist system, at least no economic competition. As ThisMatter.com explains:
"Communism and socialism affect the growth of economies, because there is no competition between businesses, and the people who manage such businesses are often political appointees, chosen more for their social and political connections than for their understanding of the businesses that they manage."
The personal finance, investment, and economics website further notes that in a communist economy, industries are often under the control of many bureaucrats, who often issue conflicting demands. Unfettered by the demands of competition, these state-controlled businesses care little about whether society wants their product or service, and do not care about costs, since these costs are paid by the government.