One can make different points to support a position without "changing" one's argument. It's known as augmentation. The extent to which banning something works is, as I initially said, greatly dependent on public support. Banning something popular drives the suppliers out of the mainstream market but they will continue to try to meet demand, usually at a higher cost and profit. Banning something widely unpopular, such as child abuse, is much more likely to have an effect since there is much less demand and far less profit to be had satisfying it. Profits don't outweigh the risk. "So does banning something work or not?" is an example of the bifurcation fallacy and indicates that you have insufficient grasp of basic verbal logic to make this worth continuing. As I have already said, bans have varying effectiveness. Go ahead and let the government point guns at people who sexually abuse kids, but see if you can control your urge to have the government point guns at people all of whom are engaging in consensual activity of which you personally disapprove.