I may be exaggerating the exact number, but it's a well known fact that infrastructure costs more in California. The subway in San Francisco's Chinatown was more expensive than most modern airports... we're being scammed.
The Chinatown subway was $600M/km, which is 3-4× "reasonable" construction costs, and fairly far from the most expensive subway, which is I believe NYC's Second Ave phase 2, at almost $4000M/km.
The US in general is a high-cost construction country (for a variety of reasons), but relative to the rest of the US, California is neither particularly expensive nor particularly cheap.
There's no reason we pay such high taxes and have so little to show for it. I get tired of the endless excuses. Every other country--even the more expensive ones like Switzerland--have more effective infrastructure projects. I honestly don't even think this is debatable. Go look at how poorly maintained practically everything in the state is--schools, roads, bridges... It doesn't make sense when we're paying such high taxes and have all the big tech companies here... I don't know why people are so comfortable with that cognitive dissonance.