There are other self-defense options as well. Lethal firearms could be entirely replaced by non-lethal. If you actually need it for defense, you can still defend yourself with it, but you’re going to have a hard time using it for murder now.
You could argue that this would increase the amount of defender deaths because they couldn’t neutralize the threat 100%, but it would drastically lower lethal firearm related crimes. Gotta weigh the options.
I’m all for self defense at a distance, I don’t want to have to risk a scuffle. If someone invades my home in the night, I don’t want to have to fight them. I want them stopped asap with as little force as possible for the safety of everyone, including the invader.