The biggest stumbling block I see that will likely always require doctor participation is in prescribing controlled substances. We require extra credentials for that because of that abuse potential.
I don't see any reason, even in theory, why "extra credentials" should have any effect on abuse.
Many other countries have far fewer drugs that require prescriptions, and some have a hierarchy of prescription drugs, with some requiring only the approval of a pharmacist or nurse, rather than a doctor. The upside to this system is lower costs and more accessible treatment. The downside is