It does in Colorado now. Universal background checks on all private sales. No FFL will do the check so any private sale is de facto banned in Colorado. Because of people like you who cannot see the problem with background checks.
Name a mass shooter that did not legally buy a gun after passing NICS. The Sandy hook shooter did not, he killed and stole to get guns. Virginia Tech, Batman Movie, Giffords and a federal judge, all passed one of your SFW background checks.
Background checks are de facto gun bans. They do NOTHING for public safety.
Background checks make progressives feel good. That is all.
The NICS system is supposed to block people who have felonies or are otherwise barred from having a gun from getting one. But it doesn’t. Why not? Because it doesn’t have complete information. If someone is deranged, hearing voices, psychotic, etc..., they would have to have a criminal record already to be blocked. Do you want to block these individuals from buying a gun or not?