While being spectacularly wrong regarding the evolution of economic systems and the propensity for revolution in advanced capitalist systems, Karl Marx was not dumb. If he had lived through the Cold War, he would have seen the major discrepencies between his theories and reality.
Marx believed that social revolution would occur following the end of the capitalist evolution, when the means of production would be concentrated in fewer hands and exploitation of workers would reach its zenith. While there are legitimate complaints regarding income gaps in many capitalist economies, however, Marx greatly underestimated the resiliency of free market systems and the extent to which labor would be dominated by management. Inasmuch as free market systems tend to overlap with democratic forms of government, the seeds of that conflict for the past fifty years have been largely absent.
Marx postulated that the advanced capitalist economies of the West would be the ones to experience communist revolutions. He firmly believed that the evolution of capitalism would create the foundation for such upheaval. The Bolshevik Revolution in Russia, combined with the absence of revolution in the advanced Western countries however, proved him wrong. Marx would neither have expected nor supported communist revolution in Russia precisely because that nation was so technically and socially primitive and lacking in a capitalist system. He understood that capitalism created wealth; he simply underestimated the degree to which that wealth would be peaceably redistributed through taxation and welfare programs.
Were Karl Marx to reappear today, he would not recognize the world. Social upheavals have occurred in the western world, but not the kind of revolution he anticipated. He would probably pop open a bottle of Yoo-Hoo, grab a copy of the Wall Street Journal, and go sit at the beach.