I don't think it's actually reasonable to assume that one can work out a country's level of economic development based off of landmass and natural resources. By those standards Japan should be poor, and Congo should be rich.

A country's wealth has much more to do with labor productivity, and labor productivity tends to be influenced by means of investment, whether capital, technological, or human. So a highly-educated workforce with access to investment capital and the most advanced technology will have a significantly higher value output than a workforce than a workforce with little to no education, little access to investment capital, and relying on manual labor for its output

Which is gets around to another point: we shouldn't be so surprised that the communist "bloc" of the 20th century was poorer than their Western capitalist neighbors because the former started out at a much lower economic level than the latter. As Stephen Kotkin writes in his Armageddon Averted it almost stands as a self evident truism that the bloc composed of Italy, France, most of Germany, Britain, Japan and the US would outperform Bulgaria, Russia, Mongolia, Cuba and Vietnam.

Even to take the USSR alone, it was one of the poorest countries in Europe in 1913, with relatively low literacy levels, an economy based mostly on agriculture (with institutions that minimized the ability to use such agricultural land with the most modern and efficient methods). To give a sense of where the Russian Empire stood in the late 19th century: its per capita GDP was 20 percent that of Britain, the average lifespan was around 30 (compared to 23 in India and 52 in Britain) and the literacy rate was about 30 percent, or roughly what the British literacy rate was a century earlier. The country was a great power and beginning to have a stronger industrial base, mostly by producing textiles, but it was still an advanced developing nation trying to catch up with developed ones, forget surpassing them.

And this is before one accounts for the massive war and upheaval that Russia experienced from 1914 through 1921. Russia actually deindistrialized and reorganized during this period. Much of Soviet economic policy in thr 1920s was focused on reattaining 1913 levels of production.

Which is not to undermine what economic development was achieved in the USSR: it did become a country with almost universal literacy, a much-improved life expectancy, and that became heavily urbanized and dependent on the industrial and service sectors rather than agriculture. But the more advanced countries mentioned at the beginning did not sit still either, but also developed economically during this period, so often Soviet economic development was trying to keep up with Western development, let alone close the gap.

Much of Eastern Europe was in a similar situation to the USSR: heavily dependent on agriculture, and lower levels of urbanization, industrialization and education than in Western Europe. The two regions that stood out where East Germany and the Czech part of Czechoslovakia, which were the richest and most industrialized parts of the Eastern Bloc, but also these areas were already richer and more industrialized before communist rule to begin with.

Ultimately, the Soviet-based focused on a command economy with a focus on heavy industry and a strong focus on output, especially in items such as steel or coal, with little regard to efficient use of input and relatively little regard for consumers allowed the Eastern Bloc to rebuild and catch up with the West to some degree aftet World War II, but did not allow them to close the gap ot surpass the latter, especially when there was a shift to greater technological sophistication, such as use of computers. Throughout this period the Eastern Bloc remained reliant on imports from the West for the most advanced capital goods.