Action Comics #1 on Ebay

Intriguing, but not the entire explanation. Not everyone in that situation turned out to be a serial killer. 

Exactly right, think about how many people were born during wartime, or had messed up parents - who never murdered anyone. It must be 99%. Though, I can't say wartime birth isn't a factor at all. Another factor I was going to mention is social media, and how connected we are now. Between 1970 and 2000, people had no mobile phones, internet was slow, and almost no social media. So not only could people not shame you for any bad actions, but people couldn't monitor you either. You could get away with a lot more I would think.

In 60', 70's, and 80's there were a lot of itinerant teens and young adults. It was probably easier to pick up victims when many highway onramps had a hitchhiker.

I think the ease of travel on the Interstate Highways was a factor.

I would hardly say "the era of serial killers has petered out." Trump has a body count of 450,000 and still rising. If anything, 2021 is on track to be a heyday for serial killers.

I also wonder if it is easier to catch people today before they become serial killers because of how common it is to see these people in chat groups, message boards, and just online. We put a lot more of our selves out there and it makes it harder to be invisible.

I can tell by the comments that no one read the linked article.

Most serial killers are men because women just like to kill one man slowly, over many many years.

I read the article and found it interesting. Just shows that every situation is complex and it is hard to pinpoint any one reason to explain a situation, especially when it comes to something as diverse as humans.