Guns are kind of old technology. Still effective, but most people are dying in their automobiles, or from some disease. The medical and pharmaceutical industrial complex are also mounting an ever impressive death toll. A gun won't help you if you are too weak to use it.
I think the social engineering strategy behind gun ownership has actually been quite effective. If a group of gun toting citizens starts to assemble in a large group, send in an agent provocateur, and the whole scene turns into chaos.
There is still a strong case for personal protection however, burglers are less likely to break into homes if there is a chance that the occupants are armed.
In summary, there are far more effective ways of culling the population than bullets.