I can actually say that if the inequities that a Marxist believes are caused by free markets aren't actually caused by free markets but by creating bubbles. Wealth redistribution actually causes an erosion of the middle class via Jenganomics. The more socialist policies that are put into place, the more it makes capitalism look like it's creating the inequities, when it fact it isn't. Economies are networks of good exchanges that are occurring. When money is funneled from the upper middle class and upper class to the lower class, the money isn't used to create investment, but acts as a battery to prop up big business by creating a rise in demand. This over time erodes the middle class. The lower tier use the money on goods and services and the Upper class just ends up with more money than they had to give up, which is why big business are pro-socialist policies because it actually helps them. If you want to actually get into whether Marxism in full implementation is broken, then I will say that it just creates a cascade of mal-investment. Truthfully, Marxism actually does the reverse effect of what Marx predicts. The longer the system goes on, the more freedoms are taken away to maintain the system, and eventually you will have an uprising of people wanting freedom to be able to trade goods and services in the way they want to. While I don't think that Marxism is capable of maintaining equity, even if it was the living standards of the individuals under it as a whole would go down.
Also, I haven't even gotten into how Keynesian economics fucks up the economy.