Unfortunately to get to that level in California means adding 60-80 lines with 20 to 40 stops each, having a train every 5 minutes, having express trains that skip stations, having the trains go fast, having busses every 10 minutes, keeping all of it clean and safe.
We'll never get that and so people will keep asking for more freeways but the train can be so much nicer.
Also, a common excuse is population density but....
Switzerland has tons of trains, is a 3x the size of the bay area with the same population
Switzerland ~8 million people
Bay Area ~8 million people
Switzerland size: 41000 sqkm
Bay Area size: 18000 sqkm
Switzerland train tracks: 5200 km
Bay Area train tracks: ??? (I think It's under 500 km so 1/10)
Traveling on a train can be great! You get more space than a plane, you can work, relax, eat, etc... Vs a car where you mostly have to spend all your time concentrating on driving.