> the Venus Project has tried to distance itself from the Marxists
It has sure tried, but it can't, because it's Marxist at it's core, and it therefore shares it's same inherent problems. It can't calculate properly properly for one, and whether the heads of those systems are politicians or programmers, the failure points are the same.
> please let's not pretend that Marxian economists are economically illiterate
Marxism from a logical perspective, will fail because it can't calculate. Soviet economists had a joke that went "We'll take over the entire world, but not New Zealand so we can know how much things cost". To that point, remember that when China was communistic, they had brought in thousands of Sears catalogs so they could allocate their resources correctly. These are things we take for granted today, but it's an attribute of economic freedom.
From an empirical perspective, Marxist economic systems have failed catastrophically in all of the 20th century. The direct result of which has been a drastic drop in living standards to starvation. Soviet Russia, China, and even North Korea had to allow at least pockets of free markets for people to survive.
So while I'm not saying that Marxists economists are economically illiterate, they have a lot to account for. And from what I've read from Mr. Fresco and the Venus Projects, including debates I've listen to, they don't seem to have an answer to these questions.
Edit: For more on the calculation problem you may want to look up "The Use of Knowledge in Society" by economist Friedrich Hayek. Incidentally, Jimmy Wales has stated that that paper was central to how the wikipedia project is managed. https://en.wikipedia.org/wiki/The_Use_of_Knowledge_in_Societ...