The problem of mass transit in CA is that our low density and distance increase the cost considerably. Neighborhoods prevent building high rises and other high density developments.
Then our transit tries to self-fund which is difficult if the intent is to keep prices low.
For example, UTC could do really well if a transit hub was clustered around a set of 20-50 story high rises with commercial, residential (affordable/mid/high end), retail, restaurants. But it requires a mentality set change in people choosing to live in apts vs houses. But if you can’t build anything and in enough quantity, the cost for space (housing/class A office space) becomes too expensive to do much.
Just came back from Hong Kong where a local told me that with a population of 7 million, the MTR transit company has 5+ million ride journeys/day. Basically, few people try to drive to work because it’s too costly (time & money).