They often prescribe brands in the sense that they will literally write the brand name in their own hand on the prescription, and that is technically literally

They often prescribe brands in the sense that they will literally write the brand name in their own hand on the prescription, and that is technically literally exactly the prescription. However, the pharmacy can substitute a perfectly equivalent drug on its own recognizance based on the doctor's prescription, but the distinction seems to technically exist. (The pharmacist position takes a lot of study and licensing as well.) I believe a doctor can or could write "no substitutions", but things aren't quite bad enough that a doctor would risk their license to do that to bolster sales for a brand or block a patient from receiving generic medication--they'd need some kind of concrete reason, like knowing or suspecting a patient is allergic to an inactive ingredient. (It's all theory, because our doctors are overworked and would never pay that kind of attention.)