Realistically, as long as airlines and I-5/SR99 exist, statistically nobody from LA will ride a train or a bus between LA and the Bay Area. For values of "nobody" in the lower quartile of trips. That's a 10-hour run at today's speeds, perhaps with some tweaks able to be done in 8ish. HSR at <3 hours (express, not stopping in flyover country in between) would be competitive with air travel for certain restricted subsets of trips, but at a huge cost (I predicted a final cost of near $100B back when the whole thing started, based simply on what it costs to build a freeway which is similar in many respects to what true HSR needs in terms of r/w, access control, and structure). Seems my WAG was right. But really, that's not much more than Europeans ultimately pay for HSR lines, and they're still building some. It's way less than what the Japanese are paying for maglev (which admittedly will be even faster).

But as a connection to what's in between (SJ Valley, with more than a million inhabitants) from each end, CAHSR *or something providing substantially similar accessibility, which might not require 200+ mph* might make transportation sense. Likewise for a run along the coast - may not be millions in population, but a not inconsiderable population exists. CAHSR has tried to straddle that fence (flyover vs intermediate traffic) and so far it's been painful. Not even arguably, it's increased the cost, because a longer run with more potential stops requires much higher speeds (maybe even 250 mph) wherever it's technically (which is mainly a matter of cost) feasible to make a politically-set (meaning not really needed) end-to-end time bogey.

Question is: do we need it? Long-run (decades to century) yes, we do. Mainly because at some point electrically powered everything is necessary to cut GHG emisssions. Sorry, electric planes can't happen (simple physics), though electrical (hybrid) assistance will help to cut emissions considerably, and jets *can* use biofuels. Battery-electric cars can (at a very substantial cost) be bought with the range to do SF-LA nonstop (barely, under perfect conditions), but (perhaps multiple) recharging stops along the way will be needed for what Most Of Us can even remotely afford extending a 6ish-hour trip to 7 or 8. And what do you do with those batteries when they have to be replaced after 100-200K miles? Yes, they can theoretically be reused (in utility-scale battery farms) or recycled, but nobody has demonstrated either of those at an industrial scale yet. Tesla - next moon shot for you?

Electric trains are about the most energy-efficient (and lowest-emission, except possibly for re-entrained dust) form of long-distance transportation, so they definitely have a bigger place in the transportation mix in the long term, if we can spend enough on them in the meantime.

But do we need it in the short term? Remembering that EVERYTHING in the US is evaluated only for the short term (long-term is the next quarter, or the next election for politicians). The answer is simple: No. While CAHSR is somewhat of an outlier in construction cost (for several reasons, technical and political), HSR in general takes a lot of money up front and, as passenger trains, will almost certainly never make enough money to pay off the capital investment. With luck (and as a long-distance run, CAHSR almost certainly won't have enough luck), it might break even on bare above-the-rail operating cost, someday. And much of the real transportation function can be accomplished at lower (though still higher than US trains mostly run now) speeds that can use less-costly infrastructure.

So will CAHSR ever be completed? I think it will, but after some battles over the Proposition language (which has a number of poison pills apparently intended to ensure that the HSR portion of the funding would never be spent - surprise!) it's possible that CAHSR could be relieved of some of the more onerous limitations. Which might allow completion to be at a lower but still sufficient standard. In which case what's being built in the Valley now will end up the straightest and nicest (test) track on the system. Which will resemble the NE Corridor or the outlying (a mix of HSR and conventional electrified rail) parts of Spanish HSR more than Chinese HSR. So why isn't CAHSR building those court cases? Or somebody?