If a society bans guns, criminals turn to knives. The government tighten the knife laws, criminals turn to things like acid or crossbows. I don't think it means "we have returned to the dark ages" because that implies you would be happier if a more modern method of murder had been used.
I'm surprised that crossbows are still legal as a good quality example in well-trained hands can be every bit as lethal as a gun, but am not surprised that, if one has decided to commit murder, the most available lethal method is sought out.
We can (probably will) ban crossbows in the near future. But people who are determined to maim or kill will always find a method.