Yep, but that does not need to be justified by a HSR expansion.

You could justify a San Benito County expansion as part of a Caltrain electrification and expansion project for a fraction of the cost and headaches.

And do the same for San Joaquin County to the Bay+Sacramento, San Bernardino County to LA, and Imperial Valley to San Diego.

In fact, this is what the CA government has been doing after treating the HSR as de facto moribund.