I want a post apocalyptic earth setting, many thousands of years in the future where civilization has no ability to create electronics. I looked into emps, gamma rays, and solar bursts but nothing seems to be lasting. I would like the apocalypse to have permanently set us back to the dark ages and even mutated some species. I’m not sure what would be scientifically plausible.
Humanity is not as smart as it was.
Homo sapiens has existed as a species for 300,000 years. It took 290,000 years before members of our species domesticated the animals we like to eat, and another 5000 before anyone made things out of metal. There were not technological innovations for a very long time.
Maybe something happened 10,000 years ago to our species. Genes for creativity and invention spread through populations. Where did those genes come from? In any case, humankind acquired powers it did not have before. Our species took over the world and made it ours.
After the apocalypse, those genes were lost and the ability to innovate with them. Homo sapiens was more the creature it was 200,000 years ago - social, clever, a tool maker, but not to the same degree. Another 200,000 years of rolling the dice with the genome will have to go by before the intelligence and creativity that humanity lost will evolve again.
Or maybe the Nephelim will return?
when the sons of God came in unto the daughters of men, and they bare children to them, the same became mighty men which were of old, men of renown.