What you say is mostly either mistaken or blindly ideological nonsense. In the late 19th and very early 20th centuries, Russia was one of the most powerful economies in the world. Under Marxist rule it first fell backward severely and only later, at immense cost in human lives and waste, industrialized and militarized to a level strong enough to make it a political competitor of the United States.

However, during this prolonged period of industrialized communist administration, it slowly hollowed itself out until (without taking a more market oriented path, regardless of what political system it maintained), the USSR was a shell masquerading as a powerful force, leading to its economic collapse. The country could have maintained the communist facade and authoritarian government, while streamlining internally through capitalistic mechanisms, but it didn't before simply dissolving, and thus the sheer poverty that it had brought itself to, absent real economic reforms, was laid bare by the end of the 1980's.

Had the Russian Empire simply maintained the pseudo-capitalistic system under authoritarian rule that was the case under the czars, or even embraced the progressive liberal socialist (but partly capitalist) system that it was starting to develop between the February 1917 revolution and the Bolshevik coup of late 1917, Russia could have grown enormously and early as both an economic and political power in a way that would have made it into a very strong power indeed leading up to the 21st century.

It was soviet communism that slowly destroyed it, but first it did make it stronger through the sheer brute force of command industrialization and militarization at all costs, these mainly being huge and completely unsustainable costs in resources, sound economic practice and human life. This industrialized strengthening under a communist command economy was not at all sustainable for the long run in the case of the USSR. It had no choice but to either rot and collapse, or reform into a guided authoritarian market economy as happened in China (coming to that momentarily)

The chaotic lunacy of post-1991 Russia had little to do with any sort of functional, organized market system. It was instead closer to a stateless anarchy with a minimal, dysfunctional facade of a working central government riding on top of it. It was only after consolidation of administrative control under Putin that Russia started to redevelop economically, though still very imperfectly because under Putin too, things remain deeply corrupt, often poorly administered, though more functional and closely controlled by central authority than they were under Yeltsin.

In the case of China, it only became a truly serious competitor to U.S. dominance once it started embracing market economics and completely abandoning centralized, command economy communism as of the 1980's. Prior to that, with the exception of a very big army and possession of the nuclear bomb (produced also at huge human cost), it was in most ways a very backward, clumsy power, albeit one with enough sheer weight to have at least some regional push.

Modern China is by far closer to a fascist, authoritarian capitalist economy than a country following anything resembling a communist path. In other words, it has more in common with the Nationalist system envisioned (but very, very ineptly implemented) by Chiang Kai Shek than with anything that the Marxist Chairman Mao had in mind. If the ghosts of both men are by chance wandering the landscape of modern China, I think it would be Chiang who you'd find nodding in approval much more often than Mao.

Ironic really, but definitely not a case of capitalism weakening political power.