It might have dropped but it's still "a high level" - 10,000 gun deaths thus far in 2017 would indicate that.
Presence of internal or external conflict seems to be the largest driver of violence.
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What should really be done is to institute a financial transaction tax that both suppresses pure speculation and taxes actual wealth generation given the largest component of take-home pay for CEOs is stock.
One thing I am uncertian of is how exactly they defined 'violent crime'. Most people only consider street crime when addressing the issue. But most death from crime is due to white collar crime. White collar crime (at least in the US) kills more people and causes more economic damage than street crime by a large margin (but is socially normalized among the upper class so rarely punished, and then only lightly).
For certain societies, banning guns might lower crime. For others, it might increase it. There's lots of complex factors in any society that can influence whether certain economic or legal policies are taken.
For example, a country with a strong militaristic culture and a law for drafting all of its citizens to the army, might have lower crime despite the prevalence of legal gun owners. All sorts of possible reasons for this.
Likewise, an island nation with strong border protection could ban guns altogether and probably see a drop in murders. It's all possible.
Societies are complex and woven with history, traditions, sub-cultures, economics, politics, and natural inclinations that can all influence the outcome of any policy for better or worse.
But as far as solving violent crime through egalitarianism, focusing on executive pay (which is a tiny fraction of the population) seems misguided. Its too small a number of people to have a noticeable affect on violent crime.
This seems to mostly solve jealousy more than anything else.
If it is basically CEOs and their board conning money out of the company, won't companies that don't engage in that kind of behavior have a competitive advantage and eventually overtake the poorly led companies?
And in reality a good CEO is worth an enormous amount of money so the actual amount that is earned and the excess that is grift is difficult to measure.