All cities of any size have places like that. Places get cleaned-up, then they die, then new places take their place. It’s the way it is, as long as there are those that will abuse substances, whether legal or not.
We don't have a generation to throw away. ...but I'll go along with your drug legalization, as long as you ban government subsidy of drugs and government paid for treatment of drug abuse and related health issues. How's that?