The problem isnt that this still is casually available. Drugs have been casually available since forever.
The problem is that pushing drug usage to the fringes makes it less safe for people who haven’t done their homework. Ironically the exact opposite of that you claimed.
The only way in the US is to have a powerful lobby that can fight to ensure broad waivers stand up in court, like the NRA: you can buy a gun and literally shoot yourself in the foot.
But if transaction, money, service, profession are all removed, then under a co-op / non profit this might work. Of course, those structures are also vulnerable to well-funded legal opponents.
Some European countries do provide a framework for this but it's more from a public health perspective and to eliminate the raison-d'être of criminal drug organizations.