Sac-San Fran, nowhere near the population density.
LA-SD and even throwing in Tijuana, no. Shorter yes, but you’d have to have 60 million people for it to make money.
The Washington DC-Boston metropolis has like 60 million people and Amtrak’s high speed commuter line, in spite of favorable demographics, is running at a loss. California has almost 40 million people but the vast bulk of them live in the San Diego-Los Angeles metropolis, which makes a statewide bullet train system a complete fantasy.