Putting pharmacies in all those places when door to door delivery exists would be insanely wasteful. Just make it easier for pharmacists to mail you your medicines.
I've spent a lot of time in tiny poor Mexican towns that manage to have a pharmacy, sometimes several. Not only that, but you can get hundreds of prescriptions over the counter that would cost thousand dollar doctors visits in the US.
I can only imagine every small town in the US would also have an economically viable pharmacy if the regulatory environment here was the same.