If there were no guns we'd be living in fantasy land. It's not a useful notion to any form of reality and never will be. Not as long as humans can build tools and have basic knowledge of Newtonian physics.
You'd have to get close to achieving the fantasy land of the first part to make much of an impact.
Here's the kicker. Even if you did get there you're reducing *gun* violence, not violence in general. Is it worth stripping fundamental rights to have a different inanimate object to blame for broken people doing what broken people are going to do? Do you think the guy who's serious ideating on murdering a crowd of people is going to stop because they can't get a firearm? If only.
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"The truth may be out there, but the lies are inside your head." Terry Pratchett