You're also assuming that the far higher number of stops for a high-speed train will only slow its average speed to 100mph. I'd bet against that, as well. Let's use your LA to SF example... you think there won't be stops in San Jose, Monterey, and San Luis Obispo (or Fresno, Modesto, and Bakersfield, if they don't use the coastal route)? Each stop will last for at least 20 minutes, more likely 30-40 (if not more for maintenance checks, handicapped passengers, bureaucratic requirements, lost children, etc). That adds about 90 minutes to the trip alone.
Even with instantaneous acceleration, that 400 mile trip at 200mph lasts 4 hours, minimum... and that's assuming that Berkeley, Pasadena, Long Beach, Anaheim and Oakland won't want their own stops as well.
But if you're so sure it can be done, then find the investors and make yourself a few hundred million.
They do, but stops are relatively short, about 20 minutes. I didn't just go from memory, I looked at the time difference between the same ICE route with and without stops. No taxi to the runway, no long wait for takeoff. Just wait a minute for a clear track and go.
Trains hand you your luggage instantaneously?
Onboard luggage lockers.
Trains do not have any security measures?
Germany has been dealing with terrorists a lot longer than we have, and the ICE is so popular it has just about 100% brand recognition.
Trains will have as many departures so that you do not have to wait longer or leave far earlier than desired?
The Frankfurt train station services 342 long-distance and 290 regional trains every day, not counting the subway and trams.
You're also assuming that the far higher number of stops for a high-speed train will only slow its average speed to 100mph. I'd bet against that, as well.
I was guessing of the ability of a 200mph train using the example of an ICE's average speed of about 100mph and top speed around only 170 (and then only on special tracks, which they don't always drive on). Not counting any stops, but the theoretical train is faster. This does count the slow-going until the train hits open track outside the city, and I didn't count that an airplane takes a while to get to cruising altitude and speed.
Such long-distance, high-speed trains usually have very few stops, if any.
But if you're so sure it can be done, then find the investors and make yourself a few hundred million.
One problem here is our cars. People might drive for four hours to get to a city where a train could get them there in less than half the time because they want to use their car when they're there. For really long distances, they would probably use planes as they're faster than trains.
But at least in Germany, even with the bad exchange rate, an ICE trip is usually less expensive than a similar-distance plane flight in the US (not even counting if you have a discount card).