Stray comments from Thomas Sowell reminded me how Marx is misunderstood in modern times, because of what his followers have done with his ideas. I had gotten even further than usual from that once-known bit of info, as my last h4eavy dose of the two was in Tom Stoppard's "The Coast Of Utopia," which included quite a bit of what an insufferable bastard Karl was. (And Bakunin, and the rest as well.)
Marx did not think business owners greedy, merely doing what they most naturally might within the system. Nor did Adam Smith think them virtuous, contrary to current impressions. Both thought the businessman much like every other category of people - worker, politician, landowner, politician.
Marx also thought that prices reflected resources and what it cost to produce an item, not greed, and didn't think that third parties should be setting prices. He and Engel believed that capitalism was a necessary next step, and that even the communist state in development, when it faltered, could be expected to revert to capitalism for some time. They believed that a nation's wealth was not a zero-sum game and that wealth could be created. He did not think that "society" was a disguised way of saying "government," and I believe criticised Rousseau on those grounds.
There may be more - I am frankly not remembering. His focus on workers owning the means of production - and more importantly, how we get there - is what separates him from today's free marketers. I think John Dewey, Laski, Brandeis, and the other control freaks of the early 20th C are more to blame for current American misunderstandings of economics. I think Marx would look at modern liberals in bewilderment and maybe contempt, and sidle over rather uneasily with the conservatives, landowners, businessmen, etc.
I am, however, well beyond any real expertise here, so correct me if I am wrong.