After world war 1, why were conditions ripe for social and political change in Russia, but not in the united states

Russia's heavy losses in WWI quickened existing calls for a political revolution against the tsar, as corruption and economic stagnation left millions of Russians in misery. By contrast, America's economy was booming during the same period, largely due to a system of free enterprise. Political "radicalism" and especially Russian "Bolshevism," then, were seen as unnecessary and dangerous.