https://www.youtube.com/watch?v=ylpDVyBpk_M
You guys are SPOT on about them not being smart enough at running wires. I know a guy and he was telling me about lead cables ... metal lead the soft metal. it had to be in to be in the 50s or 60s maybe even as late as the 80s, and it's technology from like the 20s or earlier. One of the few guys at the company who really knew how to service them.
EDIT: oh btw, these weren't just lead coated cables, these were entire trunk lines with hundred of pairs!!!
http://www3.alcatel-lucent.com/bstj/vol07-1928/articles/bstj7-2-321.pdf
http://www.electriciantalk.com/f24/lead-coated-cable-48198/