As CAR said, most people never go over the hill unless absolutely necessary.
(which is about 3 or 4 times a year for most people).
Are there people who must go through or into downtown or LAX, yes absolutely but they are the minority of the population which for L.A. County is about 10 million.
Most of the people who work where I do (next to Malibu), live in Agroua hills or Moorpark and I uesd to see a lot them in Simi Valley working for a different company.