When the government decides to, they’ll go to the gun shops, confiscate all of the 4473’s, and proceed to go door to door confiscating any and all weapons that they find. Why do you think the feds require that dealers keep those records? Easy local access to conquering forces, that’s why.
As a disclaimer, according to official government records, I have never owned or purchased a firearm of any kind. Just look for any 4473 with my name on it. And they will.
There is, in fact, a federal law that makes it illegal to confiscate the 4473s.....they would have to disregard that law.