Which communists? The USSR was infiltrated and the US then spent millions getting the bumbling mass of ethanol known as Yeltsin to win an election. They (the new capitalist government) even sieged the parliament building and sent tanks in Moscow to disperse the huge waves of protestors. It then lead to one of the worst humanitarian crisis in the modern age almost overnight.
And in China they are assuredly not capitalist, this becomes very clear once you read Deng Xiaoping. It’s Schroedinger’s China: when they do something bad they’re communists, and when they do something good (like lifting people out of poverty) they’re capitalists.
Cuba is still socialist, DPRK is still socialist, Vietnam is also reforming and opening up kinda like China did but a bit differently so still socialist