Marxism was supposed to make the average working stiff as well off as Rockefeller and the other business tycoons. Instead it made most members of the working class miserable. The only people who became well off under Marxism was....ta da...the high muckety mucks in the Communist Party. They ate well while average citizens struggled to feed their families.
Meanwhile under terrible capitalism, workers improved their lives greatly.
Even Leon Trotsky, living in New York City, was dismayed to find out that the average tenement dwellers in NYC had their own toilet. In many European countries families had to share toilets with other families.
When Lenin asked him about the prospects of communism in American, Trotksy related to him that fact.
The Marxists never thought that could happen. They never realized that when those nasty, evil "robber barons" made their millions/billions, the average worker got a better life.
Much of that gain in wealth was due to individual inventors who became rich under capitalism allowing the rest of the world to benefit from what they created. That would never have happened under Marxism.