The Soviet Union could have survived if a central political power had survived, but by the late 1970s this was becoming impossible. The collapse of the USSR resembles the collapse of many states that are overtaken by oligarchs, and the oligarchs were gaining power long before the USSR collapsed, though they were called Apparatchiks and had somewhat different roles, and less freedom-of-maneuver than the true oligarchs that emerged in the 1990s. But by the late 1970s the largest industrial powers were consolidating into a single bloc that would be able to defy the Politburo, and so Gorbachev had to worry about a coup the entire time he was in charge, and he was never able to push through the reforms that he knew were needed.

I'll post here a long excerpt from the best book on the topic.

The Struggle to Save the Soviet Economy:

Mikhail Gorvachev and the Collapse of the USSR

By Chris Miller

©2016

Page 181-183

The only force that proved strong enough to break the military-industry-agriculture coalition that dominated Soviet politics was the collapse of the Communist Party - which in turn caused the dissolution of the Soviet state. Until mid-1991, the three economic lobbies were bound together by interest, ideology, and inertia. Had Gorbachev been able to divide the coalition partners, playing one interest group against the others, he might have had more success in asserting control over the Communist Party and the Soviet state. But a strategy of divide and rule proved impossible. So long as they dominated the Communist Party, and as long as the party controlled the state, these groups’ shared interests overwhelmed any tactical alliance Gorachev could have conceivably offered. In the years after the collapse of 1991, with the military divided and discredited by the failed coup, and with industry and agriculture writhing under the pain of inflation and depression, Russian president Boris Yeltsin finally managed to split the groups, co-opting much industrial support while slashing farm subsidies and cutting military funding. Even though the Soviet Union by then no longer existed, however, Yeltsin still faced several years of resistance in his attempt to break the lobbies’ stranglehold on the federal budget and on the central bank. Only after Yeltsin shelled parliament in 1993, pushing the country to the brink of civil war, was the military-industry-agriculture coalition finally destroyed.

Was the Soviet Union simply unreformable? China’s experience proved that there is nothing inherent in Marxism-Leninism, in autocratic political systems, or in centrally planned economies, that makes a transition to a market economy impossible. In the USSR, to be sure, decades of wasteful investment left the country a burdensome economic inheritance. Yet the most damaging legacy of the command economy was not economic inefficiency, but political sclerosis. The Soviet system proved unreformable not because its economic problems were insurmountable, but because it entrusted vast political power to groups that had every reason to sabotage efforts to resolve the country’s economic dilemmas. In part, this situation was the result of the USSR’s relative wealth. When Deng took power in China, for example, the country’s farmers were on the brink of starvation. No matter what Deng did, the state of China’s countryside could hardly get worse, so China faced no built-in lobby that opposed change. By contrast, the USSR was stuck in a politically induced middle-income trap: many Soviet citizens, especially among the elite, lived decent lives that were threatened by change. Whereas Chinese farmers embraced decollectivization, Soviet farmers - who had benefited from several decades’ worth of farm subsidies - found that Gorbachev’s agriculture policies offered risks as well as rewards. A similar mechanism obstructed change in Soviet manufacturing and service enterprises.

Economic efficiency was also restrained by the relative leniency of the Communist Party during the postwar period. Under Stalin, the party had few interest groups because the Soviet dictator enforced his writ through purges and mass killings. Enterprise managers dared not miss production targets, on pain of death. The rapid rotation of cadres, facilitated by Stalin’s purges, reduced the influence of patronage networks. Brezhnev’s policy of “stability of the cadres” ended the use of the firing squad to encourage effective management. That made the Soviet system more humane, but it degraded incentives to work efficiently. Bureaucrats and managers now faced few reasons to act effectively: their firms could not go bankrupt, their salaries did not depend on performance, and they received promotions based on political connections. In China, the Cultural Revolution of the 1960s had shaken up the party and the bureaucracy, cutting back the strength of interest groups and paving the way for Deng Xiaoping’s market reforms. In the Soviet Union, by contrast, the 1960s and 1970s saw patronage network and interest groups solidify. Gorbachev inherited a system in which economic lobby groups played a larger role than ever before. Yet his powers as head of the Communist Party were weaker than any Soviet leader since the Bolsheviks took power in 1917.