Decades of socialist construction, class struggle, the eventual defeat of the working class and the restoration of capitalism, and the accumulation of rich experiences that we can draw positive and negative lessons the next time around

Socialist history is far more complex than your comically villainous caricature of it. like Samora mentioned, we can learn from both the good and the bad, there is no reason to repeat mistakes of the past while building communism. No socialist advocate for "small group of people" in charge.