Let's compare the 10 largest cities connected by the French TGV to the 10 largest cities connected to the future Cali HSR.
France:
Paris (2.18 milion)
Marseille (839,000)
Lyon (472,000)
Nice (347,000)*
Strasbourg (273,000)*
Montpellier (252,000)*
Bordeaux (232,000)*
Lille (226,000)
Rennes (210,000)
Dijon (152,000)
*LGV under construction
California:
Los Angeles (3.79 million)
San Diego (1.31 million)
San Jose (946,000)
San Francisco (805,000)
Fresno (510,000)
Sacramento (489,000)
Bakersfield (347,000)
Anaheim (336,000)
Riverside (304,000)
Stockton (292,000)
That's city populations. Not accounting for the metro areas.
In 2009, the TGV carried 122 million passengers. California is expecting the Cali HSR to reach 100 million per year by 2030. Seems very doable.