The reality is people are trained by culture to regard certain weapons as not just preferable, but necessary. If they don't have the weapon of choice handy they give up on the idea. And the reality is that some weapons are better killing tools.
Something you put in your car is easily adapted as a proper WMD, not just a building but a city block leveled and many nearby dead from high pressure vacuum exposure but we don't talk about this because we know its foolish to put ideas in heads of unstable people.
Not one pilot was particularly surprised on 9/11 beyond it had taken so long for a terrorist to employ this.
The weapons people are trained to think they need being easily available matters. It also matters with suicides given the superiority of a gun for the task.
No doubt having a gun increases suicide rates. Look no further than law enforcement and military suicide rates.
