The Soviet Communists really screwed things up in the Soviet Union.
First there was “war communism”, which involved confiscating all agricultural surplus from the peasants. The peasants didn’t like that, because they had barely enough to survive on afterwards. So they started producing less and hiding or consuming more of what they already produced. In spite of all that, the Bolsheviks won the Russian Civil War.
Next there was the “New Economic Policy” (NEP). Now only part of the peasants’ surplus was demanded from them. The idea was that the taxed produce would be sold by the state to the workers. In turn, the workers would manufacture goods that would be sold by the state to the peasants (along with other workers). This policy was referred to as the smychka or “link” between the proletariat and the peasantry.
The thing about the peasants was that, while the Russian peasant commune typically collectively owned the land it farmed and resided on, each family within it owned what they farmed. They would thus be free to sell any surplus they had. Marxists called this the “petit-bourgeois” tendency of the peasants.
Under the NEP, there was a free market for the peasants to sell their surplus (minus taxes to the Soviet state). Being a free market, prices of commodities sold within it were free to fluctuate. However, this was not the case for the non-agricultural portion of the economy (IIRC). There the prices of commodities were heavily regulated by the Soviet state.
It’s no surprise, then, that as agricultural productivity increased, food prices in the free market went down - but prices of industrial commodities remained constant (or even rose) in the face of increasing industrial productivity. This threatened the whole point of the smychka policy. The Communists took some measures to reduce industrial prices, but the so-called “scissors crisis” remained an issue.
By the late 1920s, the Communists were becoming increasingly fearful of an invasion by the Western capitalist powers and subsequent “capitalist restoration” in the Soviet Union. They figured the way to prevent this would be to build up Soviet defense capability to a much higher level. This required a build-up of heavy industry, which in turn required more people to be employed as workers instead of peasants. To make up for the lower number of peasants, agricultural productivity was to be boosted by forced collectivization. This whole effort was to be coordinated by a central plan.
There was another reason for forced collectivization - the Communists were growing increasingly wary of peasants who had become well-to-do from the free peasant market - the so-called kulaks. These peasants tended to keep produce (mainly grain) in reserve so it could be sold at higher prices during lean years. Instead of being thankful to the kulaks because more grain was available during bad harvests, the Communists ultimately classified them as “enemies of the people”. Hence the forced collectivization killed two birds with one stone.
The peasants didn’t like collectivization, however. Under collectivization, most of their surplus was to be sold to the state at much lower prices than they were getting on the free market. Furthermore, they didn’t like how the collectivization was forced. The Soviet state was only barely able to overcome peasant resistance to it, and only then through extremely repressive measures. None of this helped productivity or standard of living in general.
From that point on, the defining feature of the Soviet economic structure was its massive military-industrial complex - proportionally speaking, much more massive than that of the United States. This massive military-industrial complex was a huge hindrance on the rest of the Soviet economy. It seems that both Soviet and Western leaders were aware of this by the early 1960s, if not earlier. It may have helped inspire Eisenhower with his now-famous Farewell Address. Also Khrushchev’s effort at reaching détente with the West was spurred by a desire to dismantle the Soviet military-industrial complex and thus reallocate resources toward improving Soviet living standards.
Unfortunately, the most powerful elements of the Western leadership turned out to be those who didn’t want détente with the Soviets, and I wouldn’t be surprised if that’s because they had reason to believe that 1) the massive military-industrial complex would be continued by the Soviet leadership as long as they felt threatened by the West (led by the US) and 2) this massive military-industrial complex was unsustainable and would ultimately lead to the downfall of the Soviet state. As it turns out, they were right on both counts.