I miss PugJesus and their context/sources lol it’s hard to find anything off a Startpage search atm outside of the basic lead-made-the-Roman-empire-fall theory.
Speculating here - it’s possible that the ancient Romans who knew were about as equally numbered as today, but also like today, stubbornly willful ignorance and/or economic interests outweighed the voices calling for its cessation?
It could also be logistics - communications being fragmented and/or unable to source materials to replace the infrastructure rather than simply “not knowing”