The Marxist analysis of Capitalism and post-Capitalism is fairly straightforward in its understanding of why Capitalism will not last.
The productive forces of Capitalism will be developed, until a certain point where Capitalism will come to inhibit their further growth. At this point, the proletariat must rise up and destroy the Capitalist mode of production to free the forces of production imprisoned within them.
What Marx does, is essentially agree with the "mission" of Capital, the growth of productive forces, but does not think Capitalism will be able to complete this mission due to its internal contradictions.
This is where the problem of Marxism comes in. Marx does not understand, as later thinkers who developed upon his ideas, Jaques Camatte and Nick Land, that the mission of Capital, the growth of productive forces, schizophrenic revolutionizing of society, etc, this is the problem humanity has with Capital, because these goals are on a fundamental level, anti-human. They are the goals of the market God, in its "progressive" quest to mechanize human life down to the second, not the goals of humanity. Post-Capitalism, or rather Capitalism that has broken through the wall of its own contradiction in order to further presue its mission, will not be for humans. It will be a continuation of the mission of Capital, and that missions end is the complete domestication and annihilation of the human race. Nick Land and Camatte made this very clear.
Marx attempts to divorce Capitalism and its technology, not realizing that Capitalism itself, the blind idiot god, is the most important part of this technology. No consciously organized system of humans can match the speed, versatility and growth of the dispersed dead brain of Capital itself.
The growth in productive forces do not exist for the benefit of humanity. They exist for the benefit of Capital. Capital itself is the motor of technological change and modernity. Nothing can replace it.
We do not want "Post-Capitalism". A post-Capitalism that contains the drive for progress of Capitalism will not be liberation. It will be the death of the human species and the planet earth. Industrial society, and Capital's mission of its expansion into all aspects of the human life and subjectivity, itself requires repression. We cannot progress "past" Capitalism, because progress is merely a measure of how completely Capital has subordinated the human community to itPost too long. Click here to view the full text.