Good thing LA is nicer than I used to think.
In places like London, to my limited knowledge public transport is the only valid choice for transportation, as car traffic is in constant jam, parking is impossible to find and costs a fortune.
Countries like Belgium and Netherlands are highly urbanised and from my experience it's the same story - you do not take a car to go to work (if you work in the city/downtown). People even have jobs that they have in different cities and they take express trains everyday.
I agree though that US's suburban and car-centric model, with endless cul-de-sacs is not designed to have public transport. To retrofit public transport into this - is a colossal task, though it's also an effort to change peoples minds, that not relying on a car is "an attack on freedom" and public transport is not only for poor people.
In a dense city like NYC, public transportation is the obvious choice. In a semi-dense city like Seattle, public transportation is a viable choice. In a nebulous agglomeration like LA, public transportation is hard to rely on.