I don’t agree with the argument because Japan was connecting cities that already had, or built out, incredible public transport, and not a city like LA which is almost designed to make public transport as ineffective as possible. I’m not sure LA-SF will be as effective when the rider has to then rent a car on the LA side at least, which means it’s almost certainly cost and maybe even time effective to just drive.

The argument that you’re pointing out is a defense against the loud criticism CA HSR is receiving, and is actually a valid argument…if we had to criticize stuff, when you consider the cost inefficiency of a lot of the money being poured into roads, CA HSR would not be on the top of the list of public infra projects to criticize.