Congrats! You've just pointed (one of the many reasons) why Marx's communism didn't establish itself strongly in Russia! At different periods one might call Russia's Communist movement Leninist, Stalinist, etc., but you'd struggle to call it rightfully Marxist.

You are right in stating that the Russian Empire was behind most of the Western world in industrializing. To add to that, Russia suffered significant losses during the Great War after it entered in 1914. Eventually, in 1917, public dissent forced the Empire to withdraw. Civil war broke out against the Bolsheviks, a collection of workers organized in soviets (think unions), led by Marxists Vladmir Lenin, Leon Trotsky and the like. After a few early successes, they established a temporary "War Communism" government. It attempted to centralize much of the economy to stabilize it during the revolution, but when the last parts of the war ended in 1922, the Russian economy was just fractions of what it had been before WWI.

To remedy this, Lenin instituted a restricted brand of capitalism generically called the "New Economic Policy." It effectively restored agricultural production to pre-war levels. Lenin knew that this was opposed to a Marxist society, but recognized it as essential to creating the right conditions for one to exist. However, when Josef Stalin came to power, he abolished the program in 1928. He saw that the USSR still lagged behind other countries in industrial production, and so instituted the first of several 5-year plans to encourage industrial growth. This program returned to a planned, centralized economy, turning what Lenin had intended as a stepping stone into the final process.

Marx himself didn't even expect Russia to be the first to champion "communism." He expected successful revolutions in Germany and France, but only got to see brief, failed attempts at movements in Western Europe during his time.

TL;DR The type of communism Marx described with his class conflicts never existed in Russia for this very reason. Early leaders tried to establish the economic climate to transition into communism, but the degree of government control required for this prevented the transition from actually happening.

A couple of thoughts:

• While Russia was behind much of Europe in terms of industry, its pace of industrialisation prior to WWI was ramping up a bit and during the war industry experienced another surge (once the government gave up on the idea of importing the bulk of their munitions etc.). Norman Stone discusses this at length in his book the the Eastern Front of WWI. So while Russia's industrial working class was small, it was growing and in some respects its level of discontent might have been higher than more established working classes in other European countries.

• Communism/socialism was perhaps appealing in the Russian context because a lot of other forms of opposition to the government were either seen as ineffectual or defeated. So you already have various democratic types (for want of a better catch all term) beating their heads against a wall in the Duma. Trying to rally people around the church or nationalism would have been playing the state's game (I think the Black Hundreds could be seen this way). Socialism was new and hadn't been defeated yet (another reasonably common stream of opposition was anarchism, which I'll admit I don't know much about). It was also reasonably popular in areas/circles outside Russia during the period so there was a fair bit of discussion to be had about it. Russia's relatively late abandonment of certain elements of feudalism, like serfdom, probably also stunted the growth of other political movements - for example there wasn't a strong/large middle class.

• The Russian Communists to an extent were influenced by Russian agrarian socialists like the narodniks (the Social Revolutionaries were the sort of mainstream inheritors of this political stream). Put simply the narodniks were socialists without the industrial orientation - they thought the revolution would come from the peasantry. A certain amount of this idea that wisdom/power could come from the peasants didn't have socialist origins either - it was a seperate philosophy. Lenin and the Bolsheviks appeal to the peasantry and calls for an alliance between peasants and workers was a clear follow on from this.