[achierius]

> Meanwhile, the supply chain for the pre-Roman and post-Roman worlds were not very different.

This isn't true! We know of huge differences between who was producing what goods and where between Roman and post-Roman Britain. To give one example: ceramic production came to a complete halt, and people essentially had to make do with whatever pre-exiting ceramics they had had beforehand. Sure, an agricultural worker living on their own land off in the countryside might not have noticed a huge difference -- but someone who had been living by a legionary fortress, or one of the primary imperial administrative centers, or in one of the burgeoning villas, certainly would have had to make significant changes across the period.

[kibwen]

Yes, I'm guilty of painting with an overbroad brush here in an attempt to emphasize the difference in scale between then and now. It's not the case that the collapse of Roman authority had no effect on the people of the former territories; it certainly led to an indisputable loss of living conditions across the board, including in industrial output. But my point is that, in the event of a modern collapse, we aren't going to revert to some "checkpoint" of irreversible technological progress; we could just as likely revert to the living conditions of a denizen of the remnants of the Eastern empire as of 600 AD (and that might be an optimistic outcome!). Technological progress is not a one-way street, is my meaning, and from our lofty perch, we are entirely capable of crashing hard to Earth.