You are of course correct that no changes to the facts on the ground will happen quickly, and if you assume New York State Rifle & Pistol Association v. Bruen does not get enforced, maybe not even in New York state but like MacDonald not outside of Illinois (Chicago used to have a similar ban on simple gun ownership) I'm not going to argue with you before we have evidence, very possibly years from now.
But in theory today's 7 modern slave states will be dragged kicking and screaming into the same sorts of polices that apply to the other 43 states in the nation. And I think this will be good, "'A house divided against itself cannot stand.' I believe this government cannot endure, permanently half slave and half free." (Lincoln, who implicitly launched the nation's second wave of gun control.)