We often compare the difference in crime between US and Europe, or US and Canada as a direct result of the gun policy (even this article mentions this). But there are many differences between these regions. Canada and European countries all have much stronger social safety nets and typically a more close society in general (not trying to make a race homogeneity argument but one of walkability). I wish more conversation would revolve around this, but I'm afraid of the complexity in this (because you have to solve a lot of problems) makes this unattractive. But if the problems were simple to solve they probably would have been solved. Everything is highly multifactored these days.
There has actually been a large trend of decreasing crime since the 90's, when politicians talked about "super predators." A lot of research has been done on this and there's been been discussions if it is things like the decrease of lead in the air, abortions, or other things, but generally it doesn't seem that "tough on crime" was the dominating factor.
Another interesting statistic is that most Americans believe crime is increasing year over year despite the reverse happening. It's a good example of perception bias and probably is one of those factors mentioned above.
https://www.pewresearch.org/short-reads/2020/11/20/facts-abo...