Karl Marx and Adam Smith both had remarkable ideas about how economies work, and both made major contributions to economic thinking. Neither, of course, had a complete "solution" and both were toiling in a completely different economic environment than exists today. I am a great proponent of filtering bathwater to avoid ejecting unformed humans onto the scrapheap. I, thus, reject ill-considered wholesale disregard of economic concepts that have empirical bases. Which is to say, I'm not an absolutist.
Both capitalism and socialism have provided valuable contributions of the moral, ethical, and practical understanding of economic activity - as have other systems. For example, Mussolini was famous for "making the trains run on time." A centralized economy can be quite effective for making bold changes and redirecting labor to goals. China, currently, and other authoritarian countries have demonstrated that. China has, in the last 10 years, poured more concrete than the US did in half a century or more, and has radically reshaped its infrastructure and military. For good and ill, that is effective.
The goal of the government must be to take the most effective elements and use them for the good of the greatest number. Marx was famous for the borrowed dictum "from each according to his abilities, to each according to his needs." Like Reagan's misuse of the "a rising tide floats all boats" aphorism, it is sage advice, but misapplied. Unfortunately both are tainted by the misapplication and association with unfavored economic choices.
I mentioned in an earlier post the concept of sufficiency, borrowed and shaped from the "sufficiency economy" approach of Thai King Bhumibol Adulyadej. It is a useful approach that even our advanced economy can effectively adapt:
"Development of the country must proceed in stages. First of all, there must be a foundation with the majority of the people having enough to live on by using methods and equipment which are economical but technically correct as well. When such a secure foundation is adequately ready and operational, then it can be gradually expanded and developed to raise prosperity and the economic standard to a higher level by stages."
That is, frankly, the approach that the ACA used to create exchanges for health insurance. It is no longer adequate, but it set us upon the road in the right direction. The Green New Deal, and Medicare for All are its philosophical descendants. With one eighth of our population living in poverty, it is necessary to establish a baseline for the citizenry. The same is true for health care, where a similar population are still uninsured. Those should be absolutely unacceptable statistics in the most prosperous country in the world.