Yep, pretty much. If your gun gets stolen, your homeowners would replace the gun, but the gun insurance would pay into the state to compensate for the societal cost of gun crime. At that point, you’d be off the hook for any crimes committed with “your” gun. But if you don’t report the gun as stolen, and its traced back to you, you should be criminally responsible for the gun as it is still yours (and because you have obviously not been a responsible gun owner - the gun was in a place where it could be stolen, it was stolen, and you didn’t notice it to report it). Gun insurance would cover accidental discharge that injures or kills. It would cover your fifteen year old having a mental break and shooting up his school with your gun.
I have a rider on my homeowners policy to cover art and jewelry in excess of what a normal policy would cover. Because it isn’t fair for everyone (insurance being a spread the risk thing) to pay because I like shiny things. But if I didn’t have the insurance and my jewelry were to get stolen, it would only be my problem - since insurance just wouldn’t pay out.
If my gun gets stolen, and then used in a crime, that’s a societal problem. And one that wouldn’t exist if I had not owned the gun or if I had kept in secure. So I am culpable. Requiring insurance would help pay for some of the societal costs of gun violence.
If gun violence isn’t the issue liberals think it is, insurance would indeed be dirt cheap. The industry would probably reward responsible gun owners who had secure gun safes - but a mom who keeps her handgun in her purse accessible to her five year old might pay higher rates. (Of course, she would likely lie, but if something happened, she could be prosecuted).