Chicago's gun death tally vs. Chicago's gun laws

Why, WRT to this discussion? Seems a pretty good analogy to me, and from multiple angles.
As it seems the OP has been answered already, just a question for some of the folks who are in favor of attempts to ban handguns (or whatever)…how would it work? How would you do it? Is the expectation that you’d make handguns illegal throughout the entire country, and then…what? They would all go away? Would you expect everyone to turn them in? How would you prevent new ones from coming in from Mexico or even Canada? Is the expectation that if you banned handguns, that no one would want them any more, and thus they would disappear?

I’m not being snarky here, I’m really curious how the logic of this would work? The main argument in this thread by the anti-gun folks seems to be that of course the gun laws in Chicago (or, say, DC…or many other large US cities) don’t work because the country is awash in guns, and they can simply come in from other places. I think that there is some truth to that, but mostly it’s a load of BS, but that’s neither here nor there. Let’s pretend like that’s the case, and ignore how there are more guns today with more open gun ownership laws yet violence due to guns is declining nearly everywhere in the US in the past few decades. Ok…so, you ban handguns in the US, and then what happens? There are hundreds of millions of the things out there, after all, and millions of owners. How do you get them on board to peacefully turn in their guns (IS that the plan btw?) and, having turned them in, never attempt to posses one again? What is the expectation (or WAG) on how many of the hundreds of millions of guns out there will be rounded up this way? 90%? 10%? Something in-between?