The thesis needs some refinement. One can get a Waymo ride from San Francisco to San Jose, though one can also argue that Bay Area is one big suburb and thus the trip does not count as inter-city, even though both SF and SJ are most certainly different cities.
That said, Waymo is indeed not the right tool for the actual inter-city trips.
You also can't do inter-city train trips in most of the US either. Inter-city autonomous car trips will almost certainly happen before the trains arrive.