This post assumes Cortana’s wipe of technology on Earth was a full-wipe and was permanent for local technology. Honestly, I’m thinking it’ll be a brief power-outage (still killing a small number of people relative to the population of ten billion/half of surviving humans post-war), but here’s assuming 343i doesn’t think about that.
To be clear, I belief that most likely she either perma-wiped everyone’s tech galaxy-wide and then used Forerunner tech to provide food, water, medicine, etc. or that it was a warning shot and was temporary. Probably the first one, as this sounds more like psychotana and would enable humanity to smoothly take her place to reclaim the Mantle in a much more reasonable and sane manner if she already has fleets of Forerunner ships, Guardians, and sentinels amongst every species in the galaxy. Reclamation would be easy-peasy then.
I see some posts talking about Cortana’s EMP on Earth and they say things like “Well, it’s not that many deaths. Maybe the ships in orbit might fall to the ground and land on people, and maybe a few millions of people died from aircraft and car crashes, but that’s all.” Ignoring the fact brushing off a few million deaths is pretty messed up, you forget a few important things:
Food
Water
Medicine
These things are just a teeeeensy bit important for not dying. Sometimes. I mean, who needs food, right? Pshaw naw man, nobody eats anymore that’s so last millennium!
The machines to harvest and process and prepare food no longer function. The machines to procure safe water for billions of people no longer function. The machines to produce medicine and every bit of medical technology (and all other technology for that matter) no longer functions. Transportation for these things no longer functions. Basic sanitation technologies no longer function.
At face value, billions of people would die within a few weeks or a few months just from this, to say nothing of the numbers killed over the very, very finite resources of these things already available, especially in a non-perishable food form. Oh wait, did I say months? I forgot about us all dying in about three days without water. My bad. I’m sure many will argue there’s bottled water and so I must be wrong about the water and implicitly wrong about everything else. But, somehow, I don’t think Walmart has enough.
Oh, and the storage of these things wouldn’t work either, so no fridges and such.
Then there is the fact that other than a few tiny groups of humans on Earth who never advance (and so we don’t want them to be our legacy) or who go around raping, murdering, and pillaging every time they get their hands on so much as a gun (we don’t want them to be our legacy either), almost nobody knows how to survive in the wild. Those that do would probably die in the early violence, anyway, due to their small numbers compared to the number of people trying to shank them for a can of beans or an MRE.
Then there is the fact Earth is a DEATH WORLD. With non-electrical technology it took us hundreds of thousands of years to get to where things like the Persian and Egyptian and Roman Empires existed and so on in population size. We corpse-dragged ourselves up to that and clung on with our teeth. And that was when we knew how to survive and thrive without electrical technology.
We don’t. So, we’d mostly just die.
The few survivors would be so spread out, they probably wouldn’t even be able to reproduce without inbreeding us all out of existence.
Then there’s the diseases from billions of rotting corpses. I’m sure that’s totally harmless, though. I mean, since when has disease been a threat?