Voluntarily..? They don't expect to starve to death, they just expect that while they do their meaningful conscious-expanding profound activities, someone else will muck around in the dirt planting and harvesting. Food comes from a store, dontcha know that? and without money everything in the store is free.
There's nothing in the scenario described by Xyrik, or the scenario described by Tem42, that says the people involved are doing only "meaningful conscious-expanding profound activities" and neglecting the necessities of life. (Nor, so far as I know, was that the intention of Marx whom you cited as a prominent exponent of similar ideas.)
Trying to do what Xyrik describes might produce a lot of starving-to-death (1) because no one has yet come up with a coordination mechanism better than markets for deciding how much effort to put into what, and (2)...
How much money would it take to engineer biological immortality for at least half of the world's population, within 20 years, with 99% confidence?