When Marxism was the dominant ideology of resistance to capitalism and imperialism, it had a grand narrative of history, a cousin of the Christian narrative, in which "the last shall be first, and the first last: for many be called, but few chosen" (Matt. 20:16), a narrative whose protagonist is the proletarian vanguard inspired by an eschatological vision.
Then, many Marxists, for good and bad reasons, had a crisis of faith, the crisis of which Khomeini took note, and they turned to a new myth, the myth of Western Liberal Democracy as the End of History, the myth of which Francis Fukuyama is the best known narrator. In short, they became liberals, whether or not they knew that they did.
Historical materialism as a social theory has become better, having shed the myth of the End of History; and yet, it has fewer adherents than before, and many of the remaining adherents are intellectuals who are not in a position to lead workers and farmers, estranged from them by income, education, secularism, and other dividers. Historical materialists must find a way to overcome this estrangement.