I could take a train from Marseille to Brussels -- but why would I? I can spend almost 7 hours on a train or 1.25 hours on an airplane AND I don't have to drive all the way into Marseille, find a place to leave my car and risk getting attacked or robbed in the station [1][2]
> Train stations are also in the middle of each city, saving you about an hour of time on each end
That's assuming that you actually want to be in the middle of each city.
SFO to Cupertino by car is about 50 minutes.
Downtown San Francisco to Cupertino is roughly double that.
Not everyone traveling to San Francisco (or LA) actually wants to be in the city center. LAX to Santa Monica, Venice or most other west LA destinations is faster than downtown Los Angeles to those areas. LAX to Long Beach is faster than from downtown LA.
[1] http://ktla.com/2017/10/01/at-least-2-dead-after-knife-attac... [2] https://www.nytimes.com/2017/09/17/world/europe/marseille-fr...
There are other industries attempting to solve transportation and environmental problems in more general ways.
Then you need to not take any federal funds, because if you do you'll be forced to buy everything from domestic manufacturers, which treat you exactly as you'd expect a captive audience to be treated. (This is why the US's shipbuilding industry is confined to government contracts and vessels that are below the minimum size to be covered by the Jones Act.) If you take federal money, also expect expensive and lengthy procurement grievances regardless of the merits. California probably has a similar state law, plus all sorts of others (e.g. CEQA), and the BANANAs are very experienced at wielding them.
Add all the union contracts that mandate excessive staffing, constant handing off of work between jurisdictions, etc. and you're paying ten times as much per kilometer vs. a comparable project in a high-wage EU country.
But it needs to be said that SFO<->LAX is, at just 300 miles, and with the high demand shown by such startups, a perfect example of everything that is wrong with transportation in the US.
Compare Berlin<->Munich which happens to be almost exactly the same distance: even with some political compromises requiring the trains to stop in towns along the route that planners would rather have avoided, total travel time is only 3 1/2 hours. Train stations are also in the middle of each city, saving you about an hour of time on each end. And you can just hop onto any train without booking in advance, without going through security, without discarding your bottle of water, without the yoga-like contortions of economy class, and without the existential threat of not having internet for two hours.
That even an environmentally friendly US state such as California can't get its act together, and instead "solves" its traffic needs in the most resource-intensive ways available, is a scathing indictment of the US' lost faith in the power of government to solve collective action problems.