The idea that you have to quit drugs to recover from addiction has become old-fashioned, and treatment centers that insist on abstinence are disappearing. In California, changes in state law have made it virtually impossible for any program that accepts public funds to push clients to quit using. 

This permissive approach may be why California has more people living on the street than any other state in the country.  

Source: Leighton Woodhouse, RealClearInvestigations November 16, 2022