Pharmacists in the U.S. put up a legal moat. They have to be PharmDs.

Never mind that computers can cross-check for problems between medicarions that are contraindicated.

Never mind that in Australia, you only need a specialty bachelor, exam, and one-year paid internship.

Never mind that in Taiwan, doctors can have their nurses dispense many medicines and you can also go to a store without prescription and pick up many kinds of medicines (except stuff like painkillers above acetaminophen or ibuprofen in strength).

There likely can be legal moats put in place to hold.