Does the USA have better selection of brand name drugs and generics?

Yes and no.

The yes. Why does the USA have a wider selection? Many foreign countries limit selection to better negotiate low prices. Doctors maintain a drug list to treat various medical conditions. If a particular drug isn’t on the list there are substitutes on the list.

For example in Thailand eletriptan is on the list but rizatriptan is not on the drug list for treating migraines. As a result eletriptan is substituted for rizatriptan.

Patients and local pharmacies also purchase medications from international pharmacies.

The no. Some foreign countries approve generics earlier then the USA. As a result more low-cost generic options are available for high cost drugs such as Sovaldi and Harvoni.