I might be completely wrong but no ammo such as 9mm will also mean less 9mm guns sold. Of course there are people who buy guns not knowing there is no ammo available. Me, I sold off guns to consolidate my ammo calibers. I did this so I could buy more ammo in more common calibers. That may be a good decision or it may be a bad decision as 9mm is no where to be found which is almost all my handguns.
Conversely I keep 27 calibers on hand. So there is always something I can shoot and bullets I can get. I doubt I will see a run on 455 webley anytime soon. Unless @cubrock gets involved