The LA metropolitan area may not have as high a density as SF, NY, or Chicago, but that's primarily because it's several times the geographic size of those metropolitan areas and includes lots of uninhabited space. Many parts of LA are just as dense as similar areas of SF, NY, or Chicago.
Te type of customers who would use Uber in LA live in the high-density areas (generally K-town, Hollywood, West LA, and DTLA), and Uber does well in those areas. For anyone living in the low-medium density areas, i.e., the suburbs, Uber simply isn't economical.
