First off, I don't believe that I am anywhere close to being clueless on the subject. In fact, I've probably been involved with more addicts than most on this board, at least from a clinical standpoint.
Second. Cure? No. Have a significant impact towards their recovery by nearly eliminating the comfortable environment from which they found it to begin with? Yes. Could the seek out another source? Absolutely, but it will definitely be harder. No one is saying its THE fix, but it should be part of it. I'm not sure what your argument would be against this...