Sorry John, but I completely disagree with you. Probably not surprisingly!
Your solution, because you aren't seeing police do what you think they should do, is to tell them a lie about a fictional friend with a baby and some needles going to the media. And you expect from the OP telling them that, they will "gently" guide him away from his fictional friend going to the media and hope that he isn't involved in the criminality and was looking for a tip-off that the police know about his actions.
Doing this would jeopardize any such investigation into the suspects.
Of course there isn't a time limit on how long criminals are allowed to operate openly and without hassle but that is tied in with all police actions having to be proportionate, legal and them being accountable for their actions or inaction's. Sometimes a criminal is allowed to continue their activity if it means the authorities are gaining further evidence to strengthen the prosecution to increase the chance of conviction and to provide evidence of more serious offences. But they have to be held accountable for their decisions to allow the criminal activity to continue.
But I don't see what that part has to do with the OP's complaint, as the information he has regarding potential drug use / supply at that address, is circumstantial and is not evidence of any offences.
I'm afraid I don't understand what you mean when you say " Or they have to trust the public, especially those directly affected by the crime, as in the OP".