SF to San Diego someday. Nowhere to nowhere for the first 5 years.
If you look at the numbers, and the assumptions behind them, you'll find the system will never break even. Not even if it always runs at 100% capacity.
It won't be as cheap as flying, and won't be as fast. The other absolute certainty is that it will cost far more than the 67 billion estimate. The last big CA public works project was the new bay bridge, estimate was 1 billion, ended up at 7 billion, and it's screwed up, badly screwed up.