Based on how Prop 13 works, creating new developments is exactly what you need to do to sustain your tax base, because a brand new building can't be paying an amount of tax locked in 30 years ago, and a developer who wants to take an existing property and add more units is one of the only buyers that would be able to value a property with a locked in assessment value more than the existing owner does and thereby cause them to sell and reset the rate.
> As a result, LA now has 1 house for every 2-3 people, and nearly 2 parking spaces for every 1 person
The parking spaces are the nature of the geography. Southern California is bordered by Arizona and Nevada, i.e. the desert, and then on the other side of the desert are the rocky mountains. Even the inland parts of SoCal are mountainous and dry. This picture tells the story:
https://science.nasa.gov/earth/earth-observatory/city-lights...
A viable regional mass transit network requires a threshold amount of population density that you're never going to get in a region that looks like that outside of localized pockets, and localized pockets means everybody in them still needs a car since it's the primary way to get in or out.
It also has a propensity for sprawl even without zoning restrictions that require it because a desert near a major population center is going to get filled with single family homes even if taller buildings are allowed simply because there is available empty space.
Notice that the number of parking spaces per capita is also high in San Francisco and Seattle, but not in New York.
What the restrictive zoning does is make that even worse, and make housing unaffordable as soon as you run short of empty lots.