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As an example, think of Josef Stalin's Collectivization policy. It was a disaster for the USSR; economically, industrially, socially and (given the death toll) demographically. But because it had been pushed by Josef Stalin, the USSR could not abandon it because that would have meant the Core Leader was wrong, and in such a nation, to claim that the dictator is wrong is not just unthinkable but it is to them what blasphemy is to a priest.
Xi pushed the Zero-Covid policy, so to abandon it would mean he was wrong, and his faction will not tolerate any suggestion that he is fallible, ESPECIALLY with the "election (if you want to call it that)" looming later this year. To admit that Xi is fallible would be inviting support for a rival candidate. For Xi, being absolute ruler of a broken state is better than losing power over a prosperous one.