I understand your concerns about this (living outside Portland OR) but would counter that there's plenty of chaos with the current system.

I lost my brother to heroin decades ago and the laws on the books did nothing to prevent it, and a better system could have helped prevent it.

It would have to be done "holistically" (coordinated with the legal system, policing, health care, etc) but it's technically viable. The only thing stopping us from doing it is, um, us.

Even if it wasn't truly legal, it could be vastly overhauled if it actually was about doing what it pretends to be about: protecting us from the dangers of drugs.