Who do you expect will fund these treatment programs? I seriously doubt most addicts are equipped to pay for it.
You're talking about a country where a major political party actively works to remove funds from women's healthcare. [0]
I fully agree that these substances should be legalised for the reasons you mentioned, but I think it's laughable to think present-day politicians give a shit about these people. If anything, they'd probably face substantial lobby from police unions concerned legalisation would lead to job cuts.
[0] http://www.idahostatesman.com/news/business/article145926149...