It doesn't make sense because they did a dreadful job of controlling costs. China pays between $17M and $21M per kilometer to build high-speed rail in challenging terrain, and even Europe only pays $25-39M per kilometer. [1]
California on the other hand was going to spend $100B for 840km (phase 1, beyond the central corridor on both sides) or $119M per kilometer. That's obviously 7X China's cost and 5X Europe's cost. Yes, that Europe, the one with the onerous regulations.
It's hard to point at California's staggeringly inefficient attempt as a reason why rail is bad.
A better starting point would be Via Rail's corporate plan 2017-2021 [2].
Montreal-Ottawa travel time is 13% faster by train than car, and 30% faster than air. Average fare is $48.50 CAD ($35 USD). For comparison, a flight would be $167 to $186 each way, 4X more expensive and 30% longer end to end.
Numbers are more comparable on the Toronto to Ottawa and Toronto to Montreal corridors, with train travel coming in approximately the same time end to end as a flight but 25% less expensive. This corridor is highly competitive and similar distance to SF/LA.
Rail does in fact satisfy your requirements for short trips.
And like I said before, California is actually trying to do this and completely failed: https://www.vox.com/policy-and-politics/2019/2/15/18224717/c...