Hey, even sooner than I thought. I'm glad you mentioned the kitchen knife to sidearm rift. Because the ability to kill 5 million people across a 50,000 sq. mi. radius is right in line with the lethality of a pistol's 30 yard effective range.
You see, if you go back to my example, the things I listed actually do kill and harm lots of people. More so than firearms. The difference being that your example requires hyperbole and hypotheticals.
But I won't ignore your point. I'll play fair. The reality is that when someone does decide to go on a rampage, their lethality is exceptionally low. The deadliest shooter to date amassed a tragic 32 kills and 17 wounded, requiring 19 magazines and 400 rounds to do so. Murderers are not efficient, and even if they were, are no match for the response of a federal or state tactical team, hence their suicides always coming at the first sign of response.
Conversely, an inept, blind, deaf lunatic could use a grenade to kill a dozen people by simply removing the pin. And a nuclear bomb...I mean, come on.