HSR is a non-starter for most locations, IMHO. The cost is way too high for it to be functional.
Hyperloop is, from what I understand, way more flexible than HSR, and just as fast (or faster), with less of the overhead. That would make it a good replacement for larger citys like LA or NYC or even in metroplexes like SD-LA and the whole Beltway on the East Coast. It might even work for San Diego - Seattle or Boston-Miami runs.
Which is why I would suggest that if they start building it, start in NYC or LA with Proof of concept. The problem is, that nobody is going to build semi-permanent infrastructure for Proof of concept, as it is really egg-chicken problem.