That’s a reasonable proposition.
Next, we have to address the numerous externalities of recreational drug use, which are many. Exposure to children? Qualifications for employment? Professional licensing? Are all these affected?
Since young people report that they can get pot more easily than beer or cigarettes, it seems that the best way to keep pot out of their hands is to legalize it for adults; sellers of legal drugs typically card minors, whereas sellers of illegal drugs never do.
Qualifications for employment? Professional licensing?
Matters for employers and licensers, not government.