What I've started to realize about people is that you can't influence them all with deterrents. No matter how long the sentence, or how permanent the memory of the justice system (8 months in prison for robbery, 50 years later), none of that is bad enough to actually stop people committing crimes in the first place. Essentially, people aren't rational. They don't act in their own self interests. I saw this also when…
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.