From what I can remember during my brief period as a GPs receptionist, is that a pharmacist was employed for a few weeks now and then, with the intention of explaining to patients that if their meds were not the Trade name, but a generic name, they were still the same. Also, they were used to reassure patients if the doctor wanted them to change to a cheaper med, like from rabeprazole to omeprazole, for instance.
Oh yeah, I agree with you on the Heinz beans, cos supermarkets' Value brands are not a patch on Heinz, but it doesn't work like that with meds!! There would be an outcry if fluoxetine was found to be different from Prozac, for example! ;)