This reminds me a bit of a thought I had regarding how long would it take civilisation to return to it's current level of technology if we'd all be magically transferred back to the stone age retaining only our memories.
Generation one would be almost completely occupied finding the most efficient way to archive as much of that knowledge as possible, IMO... I'd imagine it might take a dozen generations or so, or more, depending on how much could be archived before that first generation passed away and took that experience with it. I see apprenticeships rampant!
Wouldn't it mostly depend on how many people died?
For example, after the destruction of world wars, most industries bounced back quickly because the knowledge was still there. Of course, that wasn't complete stone age.
Our civilization depends on the complex supply chains - you need people mining materials, people refining materials, people quality checking those materials, people providing various precise tools, people providing various precise tools for making the precise tools, people providing food for everyone, people moving everything around, people making the stuff that moves everything around, etc. etd.
So I think the first generations would have to spend time slowly building up all the components of the supply chain, while furiously breeding to return the population to the levels that allow as big professional specialization as we have today.
There is an episode of Freakonomics [1] that talks about this exact thing. The supply chain to make something as simple as a pencil is complex enough that no single person can make a pencil truly from scratch.
