> 3D printed guns are a thing as well and yet they don't show up in most annual violent crime reports.
For now in most parts of the world it's easier to acquire a gun either legally or on the "grey market" and be assured that it will work for the intended purpose than to 3D print a gun, find a shooting range to test out the gun and iterate until it works fine enough.
and don't forget the bullets.
In most part of the world, bullets are illegal. If you are getting "grey market" bullets anyway, it is easy to get a "grey market" gun.