https://books.openedition.org/pucl/1807
Big-name left-wing political theorist Jon Elster argues the world would be a better place if Marx and Freud had never lived.
It's hard for me to evaluate the Freud part.
On Marx, I think he makes a strong case. But much depends on whether some other form of revolutionary socialism would have come to occupy the political space taken up by Marxism.
Still, it's entirely possible that the absence of Marx and Marxism would have butterflied away the Bolshevik victory in 1917 (which was a near-run thing anyway), and that no other form of revolutionary socialism would have scored a comparable victory.
What makes me doubt this is that :
- socialism had broad appeal to many intellectuals and others, and
- most of the evils of Marxism are traceable to more general flaws of socialism (especially the need for a vast concentration of power to make the system work), rather than to problems specific to Marx's version.