See, that's where you're wrong. Not only does rely on an assumption that is flat out untrue, as people do get robbed and killed in America with other weapons all the time, but contrary to your claim guns can indeed be effective against guns, as cops, self defenders, and even gang members often prove.

I'm not going to bother going into the specifics on if you have a subsecond draw blah blah blah because let's be honest you don't really care, but again it has been demonstrated time and time again that guns are in fact an effective weapon against guns.

To my other point, of the four robberies that I've (or in one case a roommate) been victim of, only one was at gunpoint. One was just strong arm, two was my roommate got stabbed and then robbed, three was a home invasion (this was the one with guns), four was at knifepoint (unsuccessfully, because after #3 I picked up, you guessed it, a fucking gun.) #4 decided to walk away instead of stab me for some odd reason that "surely wasn't me drawing my gun," so I consider it a success.