Upon pondering the question I offered in my prior post, I've had a few new thoughts:
I'm not sure that a social and economic system's duration of life dictates how useful that system is to the human race. In other words, just because Anarcho-Capitalism may not last forever doesn't mean that a system of Anarcho-Capitalism is any less useful during the life of that system.
It seems that in every civilization since Mesopotamia there has been a cycle of social and political systems, and with each cycle comes a movement in the form of either progress towards a society that observes a set of universal objective moral rules or regression away from the observance of said moral rules. The validity of a system is not dependent upon the end of this cycle, as the cycle will always exist as long as humans are human. What's important is that we as humans must use reasoning and rational thinking to try to determine what these universal objective moral rules are and then practice a system which allows us to best exercise these moral rules. I don't believe that our obligation as humans to observe these moral rules is dictated by the (unpredictable level of potential for) longevity of the system these morals lead us to advocate.
So basically I'm saying that what I offered in my prior post was not a valid argument against the advocacy or practice of Anarcho-Capitalism but rather a cynical prediction that Anarcho-Capitalism would not last forever. But that it won't likely last forever doesn't mean we're any less obligated to seek out universal objective moral rules and advocate their observance! It's not about finding a political or social system that will last forever, it's about doing what's best for the human race, ourselves included.