I tend to think of conspiracy theories arising from being pretty far removed from the actual laws, like physics, that govern the universe. For instance, someone looking at a quote from a roofer might think that the guy is trying to scam him. Until that someone is on a 2 story house in the middle of an August afternoon in Virginia trying to pry up and hammer down shingles and get it to look and function good in 96 degree heat. Once you’ve done that, you’ll gladly pay someone else to do it.
And then I think modern times probably generate more conspiracy theories than existed in the past because we’ve become so disconnected from hard reality.
Then I remember that they used to sacrifice women and children to the gods in volcanoes and I quickly change my mind.