There is no proximate future where public transit makes sense in Wyoming. There are multiple where self-driving cars do.
When I was in Germany 25 years ago, a district of about 25k people (less than 1k per square mile) had multiple bus routes (4 IIRC) connecting the main town to other settlements, running through farmland. It was not unduly expensive and the locals certainly seemed to think it made sense. Children would take it to school in lieu of a dedicated school-owned service.
There's a light rail system in Rennes, France (city population about 225k; metro about 750k - https://en.wikipedia.org/wiki/Rennes) that's longer than the PATH system in the NYC area and almost as well used (https://en.wikipedia.org/wiki/List_of_metro_systems).
Even Iceland has public buses, both local and inter-city (https://www.straeto.is/en).
Last I checked, Waymo also operates exclusively in urban areas.