Many notable academics such as Karl Popper, David Prychitko, Robert C. Allen, and Francis Fukuyama argue that many of Marx's predictions have failed. Marx predicted that wages would tend to depreciate and that capitalist economies would suffer worsening economic crises leading to the ultimate overthrow of the capitalist system. The socialist revolution would occur first in the most advanced capitalist nations and once collective ownership had been established then all sources of class conflict would disappear. Instead of Marx's predictions, communist revolutions took place in undeveloped regions in Latin America and Asia instead of industrialized countries like the United States or the United Kingdom.