My understanding is that you can do fine in at least some areas of LA proper? Although I've heard there's a bias towards making public transport for the tourists, rather than the people living there because obviously everyone living there has a car or should just get one already.

It's just that in general LA has been spreading out rather than building up - I think the metropolitan area around LA probably around 60 miles wide at its widest point, and about 80 miles north to south. (This impression is made by googling google maps directions and may not be valid.) We have a huge population, but for a gigantic metropolitan area we're just not that densely populated.