For me, it's what I call the "money value of my time". As someone living in So Cal, I'll actually spend the extra time flying into and out of LAX if it means not having a layover in PHX, SLC, DEN, or wherever. An extra 2 hours, getting on and off another plane, navigating gates in a second airport, the added chance for a delay, etc., all make the 40 or so minutes I might have to take getting to LAX (assuming I'm alone and driving and not using carpool/HOV lanes) worth it. You also enjoy far more frequency, which means arriving earlier or departing later, getting more "time" on your vacation. Plus, about 90% of the time, any other airport around here (Long Beach, Santa Ana, Burbank, Ontario) are all more expensive than LAX and have infinitely fewer nonstops.