In areas like Anacostia there is no enforcement of drug laws. Drugs are dealt openly on the streets. Drugs are de facto legal in such places and are subject to observable market forces. What is quickly obvious is that people will buy the most effective drug that they can get for their money. There is little or no market for mild drugs with low addicitveness potential in Anacostia. Such a drug is already available in the form of Marijuana, but users go straight for the “good stuff” - crack, smack and speed. Legal mild drugs will not change the market.
Many of those crack addicts became so because the lesser drugs, they thought they were buying, were laced with more addictive substances, because there is no incentive for pushers to ensure a safe supply, but the high prices most drugs currently cost gives pushers the incentive to get people addicted, because no rational person would buy a drug that would cause intense addictions.