> since those who want to go direct between SF and LA will always have a direct flight as an option
Therein lies the problem. The cost of the line can't be justified unless it provides a viable alternative to flying between SF and LA, because that's the only conceivable way to get enough ridership. The problem is the distance between SF and LA means being competitive with flying in terms of travel time is incredibly difficult. To achieve parity the trains will need to average around 220 MPH, which is incredibly optimistic. Existing high speed rail lines rarely run at 200 MPH even momentarily due to high operating costs.
All this means that most trains will have to run nonstop between SF and LA to even have a hope of competing with flying. If the trains fail to draw passengers away from the airlines, ridership will be far too low to sustain the line without absurdly high subsidies.
Therein lies the problem. The cost of the line can't be justified unless it provides a viable alternative to flying between SF and LA, because that's the only conceivable way to get enough ridership. The problem is the distance between SF and LA means being competitive with flying in terms of travel time is incredibly difficult. To achieve parity the trains will need to average around 220 MPH, which is incredibly optimistic. Existing high speed rail lines rarely run at 200 MPH even momentarily due to high operating costs.
All this means that most trains will have to run nonstop between SF and LA to even have a hope of competing with flying. If the trains fail to draw passengers away from the airlines, ridership will be far too low to sustain the line without absurdly high subsidies.