Kevin Kelly theorizes that "the power of an individual to kill others has not increased over time":
A classic Hollywood trope is the evil genius madman who is using new technology he just invented to murder (or blackmail with the threat to murder) a large chunk of humanity. Always the lone evil genius works in a high tech haven, hidden from others, all by himself. At this point, the scenario is total fiction because no one can run all that technology by themselves. It is hard to keep 3 computers and a network going all by yourself. The madman's electronic door hatch probably crashes once a month, particularly if the madman just invented it. So can you invent and keep operational the death ray? No. Way. No solo genius can destroy mankind. That kind of power takes cooperation.