Pure, Unadulterated, Speculation. Every time we have a mass shooting and nothing's done the hearts of the people change. Every time someone you know shoots themself... every time there's a robbery and a gun is fired.
Even in Australia's case, you can still own a firearm; we'd do the same here. Just show that you need one for X reason and it's yours. Most firearm wielding citizens would be happy to comply with whatever's needed to keep their guns. The term "well regulated militia" comes to mind. Make it free with a background check/interview, and the unwashed unreasonable masses will comply.
You keep bringing up the 2nd amendment like it's infallible blanket that says you can go buy a pack of smokes and 13 firearms of your choosing. It's not. I'll post it right here again:
https://www.law.cornell.edu/constitution/second_amendment
Not "You get a gun just cuz". Rather "A militia is necessary; for that reason you can have a gun".
Over the years, this has been interpreted different ways depending on the courts. As we've seen in recent years with gay marriage bans being deemed illegal, African Americans getting equal rights, and the Women's Suffrage movements, as the hearts of the people change, so do the minds of the courts.
Now, again, stop the butt hurt and quit fighting something that's a last option. Find a way out of using a gun ban that's even arguably as effective as what Australia's done. I'd much rather jump on that train, but I'm not convinced it exists.