It can’t. Besides demography, Xi has wiped out his political competition. The history of what comes after a long-serving dictator who purged his generation’s political braintrust is unidirectional.
True, and Kruschev is 20 years Stalin’s junior. I’m inclined to regard him as a fluke; the wheels of power replaced him with the far-less competent Brezhnev after ten years, at which point the Soviets’ fate was sealed.
It’s an open question: if the ISSR could have both beaten the U.S. and remained intact following Stalin’s death. I don’t think they could have. Insisting on not just parity, but supremacy, may have doomed them.
The ability for Beijing is Taiwan. They really shouldn’t obsess over it. But Xi has done so, and likely can’t retreat. Which means his successor is similarly damned, and with him, his nation.