The LA County supervisors each have around 2 million constituents and control an enormous budget. These are positions with an enormous budget, a ton of power, and are largely unknown to the average person. They don't have the high profile that the Los Angeles city mayor does. People serve forever. Three of the seats have had only 2 supervisors going back to the 70's, while the other two have had 3 supervisors. If not for term limits there wouldn't be 2 new supervisors getting elected this year. The seats are also very gerrymandered to produce a Hispanic Democrat, a Black Democrat, a progressive White Democrat, and 2 Republicans.
Today former Los Angeles mayoral candidate Wendy Greuel decided not to run for the 3rd District supervisor seat, which is up this year. This should hand the seat to JFK nephew Bobby Shriver, the only heavyweight candidate who is currently in the race. Shriver has never run for anything so big, but his opposition is relatively unknown and can't raise the kind of money he can. If he manages to lose this seat against this competition, he's inept.