Arguably it wasn’t carried out in the USSR because it happened after Yeltsin’s coup dissolved it. One might argue that Gorbachev’s Perestroika would have inevitably led to that outcome, but we’ll never really know.

It hasn’t been carried out in China. China’s bourgeoisie don’t collaborate with the Chinese state so much as take orders from it. Previously:

If the state owns [the means of production], and the state also owns the money printer and also the banks (which are another form of money printing), then it’s not compelled to be run in the M-C-M' capitalist mode of production, because it doesn’t need to make a profit, or even break even.

Furthermore, the capitalists in China have virtually no political power. Just look at the number of rich people who’ve received the death sentence with reprieve, or the property developers who were left to flail and go bankrupt, or the sorry state of billionaire Jack Ma.

Also what “imperialism” was Stalin involved with, and who were the “hundreds of thousands of communist revolutionaries and Old Bolsheviks” that Stalin murdered?