That's why the police don't enforce drug laws in _particular_ areas.

What you describe is obviously already happening on a much larger scale.

I'm not sure why people have trouble grasping something this basic.

Because many of us who live in cities have experience with police being completely feckless.

I have experienced multiple times when I tell police that I have video evidence of a crime happening as well as evidence of the identity of the criminal and they won’t even look at it. I once had a cop tell me that I shouldn’t bother with a report with witnesses and evidence and a known perpetrator since it would never get investigated. That cop got punished for telling the truth, although they were 100% correct, the detective on the case never even opened the file. The detective was not punished.