The problem with that is, doctors, for the most part, don’t know jack about food supplements. In fact, most don’t even believe in them.
True, doctors do however believe in prescribing toxic drugs, with nasty side effects, controled by the corrupt FDA.
The objective is to wipe out the over the counter supplements industry. As you observed, most doctors are clueless on the topic. It's a safe bet that pharmacies would never maintain the stock levels that you find over the counter today. Certainly not at current prices after having to visit a doctor for a prescription and bother a pharmacist to fetch the goods. Further, CODEX would likely outlaw the manufacture of most items available today.