There's a decent amount of experimental evidence to counter this realisation though.

The yakuza basically never carry guns around anymore because the charges for carrying around a handgun are so high that it's just not worth it.

We always say that "well if someone wants a gun they're gonna get it", which is pretty true. But some deterrents can slow down the transition from " I don't like that guy" to "I'm going to kill him" (hell, if we stop at "going to beat him with a bat", that's still a bit better).

People aren't rational, but things like advertising works, so some form of deterrents must work too I think.