Note that I referred to Mao Zedong's China and not the China of today, which has embraced a "controlled capitalism" after their flirtation with communism failed miserably (as it always does).
Can you trust the USSR lifespan statistics? I wouldn't.
You cite other countries, none of which are under a purely communist government, because that has never worked out for anyone other than the dictators that ruled them.
I don't think statistics are the issue, or what the exact definition of a Communist is. For what it's worth, self-described Communists are still in charge in all of the countries I mentioned, with the obvious exception of Soviet Russia.
Let's step back for a moment. I think you should acknowledge that you have constructed a world where communists do battle with capitalists, and capitalists are the good guys.
That idea is outdated and increasingly ridiculous. Clearly it is a narrative that serves the interests of billionaires in West Palm Beach. I don't know that working people buy it.
Other nations have already had to face the end of empire. But we weren't brought down by Communists.
40 years ago Soviet Russia overreached in a war of choice in the Middle East. It showed the world that they did not have the military might that they projected. They eventually withdrew, defeated and disunited. The empire, already hollowed out by corruption, was now perceived as a paper tiger. It rapidly fell to pieces.
Well guess what.