> it would be great (from a self-protection point of view) if guns had never been invented

Firearms make it possible for the physically weak to stand on equal ground with the physically strong. Without a gun, a pretty girl who has never been to the gym is a target for a 250 pound muscle-bound rapist. With a gun, she is someone to avoid, because those who prey on the weak are fundamentally cowardly. Places that change the law to make firearms more ubiquitous (such as Kennesaw, GA or the entire state of Florida, both of which have made landmark strides toward greater proliferation of legally owned and carried firearms at various times) tend to see dramatic drops in their rates of violent crimes.

The invention of the handgun, coupled with the ability to carry it legally, may be the most important enhancement of personal safety against criminals who prey on their fellow human beings.