you just can't see the bigger picture.
yes supply outlets changed. But in economic terms it is reduced on many levels. The very virtue of one having to be in a "scene" indicates somewhat restricted access. In the past, any male of age could walk into his docs office and get a scrip for a cycle. Those days are long gone. The people that still really want to juice will do it. But in an aggregate sense, there are people no longer juicing because of restricted access. These would be people who want to juice "kind of" but aren't that serrious about it. A significant amount of these people would just go and use PHs or something else altogether now. This isn't to mention the fact that crackdowns and big busts do tend to ultimately affect prices which shows an effect on reducing supply. Furthermore, whether you want to attribute it to demand side or supply, a significant amount of people will not juice due to steroids being illegal-- not only specifically because of the illegal stigma but due to not being able to access clean juice, etc.. The net result is a less qty demanded; and policy makers know that. Perhaps you argue that people juice because it is illegal-- the forbidden fruit idea-- but that would be a very weak argument, not empirically supported imo.
The argument was initially put in place saying that making ephedra illegal will do nothing to people that want to use it, and this somewhat comparable steroid situation was drawn up. Again, people that are hardcore and want their ephedrine will get it. But joe consumer will no longer see Xenadrine commercials and see ephedrine in GNC and as such will just move on to other fat loss things. There will be a significant less amount of ephedrine being demanded (all else being equal). And from a "public health' stand point, this is what policy makers want. Is it very effective-- no. Is it effective to a degree-- yes. Do I support it--- no, but that does not change the economic effects of the decision.