"HSR goes from city center to city center because that's where people actually want to go." citation? Last I checked, people aren't squeamish about going all the way down to san mateo to get to SFO. OK. So let's say it takes about the same time as HSR (keeping in mind that in the real world "existing lines" are not rated for High speed, and are subject to congestion problems with existing commercial and freight routes)... The pricepoint for hyperloop is about the same as an airplane, which is half as expensive as rail travel. So, you could either take hyperloop or take HSR. The times are the same (assuming no express routes crop up to get to hyperloop), but you do still have to take some public transport or cab or whatever, is it worth it to pay half as much? I think so.
Wow does this ever miss the point. It's not that nobody is willing to drive to Hayward. It's not that Hayward is on the moon. It's not that nobody would go to Hayward to get on the Hyperloop. Millions would.
The point is that the transit time from SF to Hayward is part of the SF/LA transit time. That's all.
So if I'm in mountain view, what is the differential (public) transit time to the HSR termini/stations in Bay area, versus Hayward? How about Berkeley? Vallejo? I guess part of my point also that I'm not articulating well, is that if you're not on the HSR line (which most of the bay area isn't) you have to spend non-zero time commuting to the HSR station, too. Even if you are relatively close, say, cupertino or mountain view (closest stations: Palo Alto or San Jose) there is a commuting time-cost, too.
I'm guessing you don't live in california, do you?
edit: Oh, I think you're sort of a mentor figure to one of my friends from kindergarten (and a board member of my startup nonprofit...) HN isn't really the best venue for a nuanced discussion, if you'd like to talk about the problems with CHSR and why comparing Hyperloop to CHSR official figures is charitable to CHSR - feel free to contact me personally!