What did Karl Marx believe would happen to capitalism

Marx believed that capitalism would become worse and worse until the workers would no longer tolerate conditions forced on them by management (low pay no health0care, poor food, child labor et all) he didn't think that management would make the concessions to labor that they did (minimum wage, health-care, a 40 hour week no child labor), fun fact he thought America would become the first communist nation because conditions were so bad here when he wrote. At this pint he predicted that capitalism would be abolished by a revolt of the workers. He however rejected social Darwinism, rather he suggests that in communism everyone's human needs would be met ad hoc "From each by ability to each by need"