This seems to be saying if a solution isn't 100% effective we might as well not bother. Which seems silly to me.
I feel pretty confident in saying if guns all suddenly disappeared by magic, homicides would drop by like 70%. Sure, some people would stab people to death, others would build a pressure cooker bomb, and so on. But I don't think something needs to be perfect to be good.
Obviously there's no magic make guns disappear button, but there is a super strong correlation between the number of guns available and homicides. I think it would make sense to enact policies that over time would make guns more expensive and hard to find.
HOWEVER, it would have to pass constitutional muster, which I don't think will happen. I would wish that there was a requirement that in order to own a gun you had to be a part of a well regulated militia, and train with your weapon at least once a month. But that does not seem to be the interpretation of the Constitution, so at this point there would need to be another amendment, which has 0% chance of passing.