If the guns aren't leagal there will be less in the country for people to buy illegally or steal. They have to come from somewhere.
This notion that the AWB wasn't very effective isn't a very realistic assumption. The idea is to stop the flow of new weapons into the system. For sure there will still be a lot on the street, but why keep pumping more in?
The original AWB had plenty of holes in it. For sure it was mostly a feel good measure, but it was a step in the right direction. Gun owners get too freaked out the left is going to try to ban all guns. The vast majority of people don't want this, it won't ever happen.
You don't need a LAW 12 gauge
-spence