No they haven’t. The Khymer Rouge killed a million people and emptied cities, but couldn’t make their socialist economy work. The Chinese tried the Great Leap Forward and later the Cultural Revolution and mostly succeeded in producing little Red books and starving people by the millions. The Soviet Union and Communist regimes in Eastern Europe couldn’t keep up economically with the West: people didn’t risk their lives climbing the Berlin Wall because they forgot they were in a worker’s paradise.
One failure and flop after another- all mixed with different degrees of police state nastiness and corruption: that’s your utopia?