Regular crime is overwhelmingly the result of poor economic conditions. Govern well, uplift people's living conditions and crime naturally fades.

Crime is directly related to not necessarily poverty, but income inequality. So in a given area where class contradictions are intensified, there will be more crime.

Also note that correlation is not causation. One theory regarding causation is that this is the fallout of COINTELPRO, when the CIA and local police had disrupted revolutionary movements to prevent unification against capitalism, through provoking infighting and promoting drug abuse.

In other words, crime is artificially increased to create a lower class, and contradictions within the proletariat are exacerbated to prevent unity.

You're on the right train of thought, crime goes down with better opportunities. That's why marginalized minorities tend to have higher crime rates, not because their "race being inherently violent" like conservatives like to parrot, it's simply because of their lack of economic opportunities.

Another factor to be considered is the proper knowledge of the gun owner about gun handling, like Switzerland has, if I'm not mistaken nearly 100% of the population owning guns on the account of their obligatory military service for 2 years for men and 1 year for women and at the end of it they take and rifle with them, so the proper training with the gun is likely a factor. That being said in the US I don't see any short term solution other than stricter gun control,for there is a weird gun culture there that makes people fetishise their guns so much that they wanna create an opportunity to use them