Marx, like Freud, Nietzsche were students of What This Is. Economy became a dominant force in driving What This Is, and there was a guy, Marx, who did a really good job describing it at the time it happened. If you are a student of What This Is, you can focus on any number of angles and dimensions to see reality/your reality. But once the dazzle wears off, and sobriety returns, all the other things mediating What This Is come back into view. At this juncture you can carry your fetish for your own pet discipline, believing that It Is The Thing, disregarding other information, or you can accept that you have studied one piece of a rich and complex dynamic puzzle. There are so many things that be the human experience. The mode of production, or economy, is just one thing. To base all decisions of how best to mediate humans downriver of only that thing is not going to provide the necessary What This Is diversity to give humans a complete and healthy experience. If you want to reshape all of humanity based on principles of one of these Things (some form of [prefix]ology), you will make us sick.