The collapse of the Soviet Union was at least foreshadowed by Andrei Almarik's 'Will the Soviet Union survive till 1984?', written in 1970.
The possibility of a sudden implosion in China is clearly present. The huge focus on control of every relationship is a clear indication, the leaders fear social upheaval. The brutal reaction to the Covid outbreak underscored that.
In the initial stages, when the situation appeared most dicey, Xi disappeared from the front page of Xinhua, doubtless fearing to become a focus of popular outrage after the death of the doctor who had tried to sound the alarm.
However, the regime can claim to have lifted hundreds of millions of Chinese out of abject poverty, which is a huge achievement that helps stabilize the social compact.
That is a sharp contrast to the Russian experience during the latter Soviet period, stagnation at home and a pointless war abroad.