The enforcement of Communism ( Mao ) certainly caused the death of tens of millions ( ditto the USSR - Lenin & Stalin ) for a historic total in the order of 60 million ++ ..... I was focussing on the demise of Communism without such conflict. Perhaps there is a lesson here - nobody who experienced the Worker's Paradise mourned its demise.

As for the matter of transition to "democracy" both in the former USSR and China - that may be considered an entirely different historical mechanism. Neither Russia nor China had any experience whatsoever with democratic processes nor private property prior to the Communist take over. It will take several generations to arrive at democratic governance as we claim to practice.