The article thesis about technology impact on the prevalence of serial killers doesn't really hold up against the fact that rate of unsolved homicides has sky rocketed since the 60's [1].
One could offer a lot of speculations on how to reconcile the disappearance of "traditional' serial killers with the jump of unsolved homicides. For instance, I have read in the past articles about "experts" warning about a possible epidemic of undetected serial killers...
[1] https://www.murderdata.org/2015/01/how-many-unsolved-murders...