China's government is "very stable" until it's not. As a society, China has a long history but the central government has essentially collapsed or experienced violent revolution in 1976, 1969, 1949, 1927, 1911, 1850, 1796, 1644, etc. Perhaps we have reached "the end of history" and the Chinese Communist Party will now maintain stable control forever. Or maybe it will all fall apart again in a few decades due to resource shortages or factional power struggles or a foreign war.

The loss of a succession strategy with an elderly leader at the helm seems like a major issue.

... for everyone, Chinese or not, except the elderly leader in question.

Same for Russia.

That seems to be a recurring theme regardless of the country's economic system. We're two months away from seeing if the US still has a working succession strategy.