I mean, economics is a mathematical profession. It's hard for me to take his storytelling about things like the freedom of hunter-gatherers and such seriously when I know he wasn't rigorous in the things that are easier to check. Never mind the, err, implementation problems in basically every attempted revolution until somewhere around the point where the Nordic states found a way to subsidize it with resource extraction and found a voluntary version.
It strikes me as incurious to dismiss an entire field of thought because there were errors in a mathematical manuscript, especially when you clearly don't understand the fundamental concepts (I don't mean this as a dig. You just haven't learned them.). Marxism isn't the writings of a long dead guy in England in 1860. It's a living, breathing school of thought that's evolved significantly since then. What you're doing is akin to finding an error in Smith or Ricardo's [edit: unpublished manuscripts, not completed work] work (of which there were many) and using those errors to dismiss all of orthodox economics.
The revolutionary approaches have not succeeded thus far, granted. There is a branch of Marxism about revolution, but what we're talking about here is a description of capitalism. Marxist revolutionary activities have nothing to do with how potent that analysis is.
