In the West, while the military industry initially pushed computer development, private companies quickly adapted those technologies for the consumer market. Over time, the Western consumer market became vastly larger than the military one.
In the USSR, this cross-pollination wasn't possible because anything that even touched the military was immediately classified as a state secret. This obsession with secrecy even affected civilian infrastructure like nuclear power plants. Plant operators weren't fully trained on how the systems worked under extreme conditions, and they were kept completely in the dark about inherent design flaws—because in the Soviet system, everything was by definition perfect and superior to the West.
Furthermore, because the consumer market was strictly controlled by the government and the party, the Soviet economy lacked any organic market signals regarding what people actually wanted or needed. Apparatchiks had to look elsewhere for data, so they resorted to copying Western solutions—sometimes just copying the basic concept (like a radio where users could choose their own stations), and sometimes cloning the entire machine.
While Soviet scientists had some highly innovative and interesting ideas in the beginning, central planners eventually decided it was faster and easier to copy a Western solution that was already 5, 10, or 15 years ahead in mass production.