

There could be two ways to address this problem. One is asteroid mining, which has the potential to be extremely lucrative because there are lots of asteroids with huge metal deposits.
Another is discovering new conductors. There’s been progress in developing conductive plastics. https://phys.org/news/2022-10-scientists-material-plastic-metal.html
Absolutely yes. One of my favorite anime is GATE. It has a portal open from a alternate world at Roman level technology with legions and classical architecture, but it has dragons, elves, and magic and they send an army through to invade modern day Japan. The counter-attack is insane. Do a google search for “massacre of alnus hill”