So, why did Marx's roadplan fail as miserably as it did? What were his actual goals?
His actual goal was the elimination of class, and he spent a -lot- of time talking about "rentier" classes. Libertarians, this should immediately call to mind a phrase we use quite frequently in regard to anti-free market behavior: Rent seeking.
I'll spare you the Socratic dialogue in which I try to make you come to the conclusion yourself: Marx apparently failed to recognize that rent is a fully generalized phenomenon.
Marx recognized land as a rental property. Did he recognize that a bureaucratic job working for the central state-owned bank deciding who gets and doesn't get credit is a rental property as well? That the people responsible for assigning transportation routes and communication lines had power over those who had to request things from them?
We can talk about Stalin and Lenin, but they aren't really the issue with Marxism; they demonstrate one potential way the implementation can go very, very wrong. What they don't demonstrate is that the implementation Marx laid out is itself very, very wrong.
Government power is rental power. A centralized credit agency is staffed by a rentier class by virtue of the fact that they staff a centralized credit agency. What strangles Marxist states isn't just the dictators, it's the millions of petty bureaucrats who become the new bourgeois, the new rentier class - there's a reason bribery becomes standard in such societies, it's the best way the rentier class has of extracting rent for their rental property.
An incomplete list of rental properties:
Gender in a genuinely sexist society
Occupational power/discretionary power
A rental property can be either stable or transitory, replicable or non-replicable, transferable or non-transferable.
Communism in its most extreme Harrison Bergeron implementation is the complete elimination of -all- forms of rent. A more reasonable communism is just the minimization of certain kinds of rent - eliminating stable, non-replicable, transferable rental properties. Land, (some) forms of intellectual property, occupational power, for the big three that share this deadly trio of properties. The inclusion of capital goods is a mistake for precisely the same reason as the inclusion of education would be a mistake - it's a replicable rental property. As long as replication isn't unduly constrained, at least.
Every implementation of Marx to date has -omitted- attention paid to occupational power, because Marx himself does little to address the potential harm, and has become overrun by bureaucrats.
But once we consider the deadly trio of properties - aren't these precisely the things libertarianism as a whole has been incapable of coming to conclusions on? Intellectual property ownership of, for example, a book isn't a problem - you weren't going to write -that- book anyways, you were going to write a completely different one. We'd need to fill the universe with nanobot authors before this actually started to become an issue. However, owning -process- -is- a problem; there are a finite number of ways to feasibly manufacture penicillin. Intellectual property laws have historically solved this dilemma by eliminating -stability- from this aspect of intellectual property; you have a finite amount of time to capitalize on your patent before it ceases to be functional. (In today's society, that amount of time is probably too high, since a better something will probably come along long before the patent expires, but that's another discussion entirely.) Modern society, however, has begun to -copyright-, rather than -patent-, process. Witness the massive intellectual capital wars happening between major corporations right now.
I, on great consideration, define communism to be, quite simply, a special case of the general case of libertarianism. (Yes, Marx hated libertarians, but libertarian in his day meant anarchist; anarchism now being considered one of -many- different ideologies in the very broad category we loosely refer to as "libertarian"). Existing implementations of communism were not in fact implementations of communism, but implementation of a deeply and fatally laid out -process- by which to -arrive- at communism, which ultimately exacerbated the very classist society they sought to eliminate.
Communism isn't incompatible with the free market. The modern left isn't Left; they're the same bourgeois that they've always been, and their support of the already-shown-to-be-flawed Marxist -approach- to -arriving- at communism, combined with their opposition to libertarian philosophy more broadly, demonstrates their desire to perpetuate the classist society we live in. (Not that this is unexpected from a group of people who generally take -pleasure- in being referred to as "elitist.")
The goal is the elimination of class. This is not an inherently anti-libertarian concept; we take great issue with class, we just don't generally call it that.