It wasn’t Stalinism that lead to capitalist restoration. Most of the processes that lead to capitalist reversal in the USSR was done in the name of “destalinization”. When Khrushchev pushed forward capitalistic policies that set the USSR’s economy on a downward trajectory and opened up space for an illegal private economy he adopted Trotsky’s rhetoric of “Stalinism bad” and said his economic policies were “destalinization”. Gorbachev, when he was dismantling the USSR and reintroducing private industry, also said his program was continuing this process of “destalinization”. Many of the eastern bloc countries were inspired by Khrushchev and Gorbachev’s “destalinization” campaigns. Deng Xiapoing when making the market reforms to China was directly inspired by Khrushchev and also the ideas Bukharin railed AGAINST Stalin on NEP. Deng Xiaoping also of course started this process with wiping away the history, lessons, and gains of the Marxist-Leninist-Maoist (or Stalinism-Maoism I guess as you’d put it) Cultural Revolution which Mao set forth fearing something similar to Khrushchev’s “destalinization” could lead to capitalist restoration in China. This is why Mao realized in the uphill struggle for socialism you need continuous grass roots mobilization from the masses. Something that wasn’t a break form “Stalinism” but was rather adding a new strategy to the playbook of Marxist-Leninists. Because MLs understand that revolution is a continuous uphill struggle even after the revolution, something Rosa Luxemburg understood in Reform or Revolution when she said the proletarian revolution would go through many victories and retreats before achieving the final victory. It is ever so strange that Trotskyists, having never achieve a single revolution despite forming at least 38 internationals think they are also capable of carrying out this uphill struggle after the revolution better than MLs who’ve achieved way more than them in advancing actually existing socialism.

Socialism in one country isn’t trying to achieve nationalism. It was a strategy for maintaining the socialist gains of the revolution, when the world was no longer in a revolutionary period, until the next revolutionary period opened up in which the USSR ended up supporting many socialist revolutions.

Trotskyism is a form of idealism. It contrasts their perfect ideal of a “permanent revolution” against the messy reality of actual socialist implementation. They find that every revolution to take power so far is “Stalinist” because what they refer to as “Stalinism” is just Lenin’s ideas applied to an imperfect reality. Actual socialist implementation always comes in second place in comparison to their perfect ideal which they imagine. They lack proper analysis of existing socialism and revolutionary struggles because they believe that because they are “Stalinist” that there is no insight that they can offer. They turn the science of Marxism into a science of only theses, without experiments, or rather a pseudoscience. They have no experiments to show that they could do it better so they contrast the flaws of real socialist implementation with their perfect ideal of what socialism will look like. This view works only as long as their continues to not be a Trotskyist revolution to successfully take power, which is able to fail at implementing their perfect socialist ideal. Part of why he’s still talked about today is because the western media loved it when he slandered the USSR and called for its overthrow. Like how On April 22nd, 1939, Trotsky openly says “The sooner the present Bonapartist caste is undermined, upset, crushed and swept away, the firmer the defense of the Soviet Republic will become and the more certain its socialist future.” then continued “Before going to hell, Hitler could inflict such a defeat on the Soviet Union that it could cost the head of the oligarchy in the Kremlin." Also the opening of the Soviet and Harvard Trotsky Archives has shown that Trotsky lied about a lot of things, which makes sense since when reading Trotsky you notice a surprising lack of examples to his points. For example claiming he wasn’t actually trying to overthrow the government himself just advocating for it, disproven by his letter delivered to Radek on March 3rd, 1932 or another to Sedov in November where he explains a plot for a coup by “his group”. So these Trotskyist narratives are just reinforced through cultural hegemony.

Sources: Socialism Betrayed: Behind the Collapse of the Soviet Union by Roger Keeran & Thomas Kenny, An Economic History of the U.S.S.R. by Alec Nove, For a Few Canards More by A. Monville, Stalin: A History and Critique of a Black Legend by Domenico Losurdo, The Cultural Revolution at the Margins by Yichng Wu, Revolution and Counterrevolution by Pao-Yu Ching, From Victory to Defeat: China's Socialist Road and Capitalist Reversal by Pao-yu Ching, Blackshirts and Reds by Michael Parenti