Here’s a little thought experiment I came up with: let’s say the population of a large city under a communist government was suddenly transported back to prehistoric times. None of their technology came with them, only the knowledge in their brains. Let’s assume they survive, would they be able to keep living under some sort of Marxist-leninist/communist ideology? In the complete absence of technology, do you think a large scale communist society can be maintained, or would it necessarily have to dissolve into something more akin to “tribal communism”? Would the tribes they revert into start warring with each other for resources like actual prehistoric tribes did? Do you think the people in this situation would be able to hold on to communist ideals from a mental perspective, or would people start wanting a capitalist or other system?
we only need to compute labour time values if we want a monetary system. in a primitive communist society the goods needed are socially hunted/gathered/cultivated/built and shared by all. if you add your modern knowledge you will improve comfort and reduce the needed labour, but if you don’t change the economic system, thee needed goods will be communal, as before, and no need to calculate value.