The political graveyards of California are littered with the bones of candidates who tried to get elected to statewide office on the basis of their own great wealth. Steve Westly, Al Checchi, Jane Harmon, Michael Huffington, Darrell Issa ... lots of people though they could buy the job of governor or senator. Most of them failed -- in part because they couldn't craft a message that appealed to the voters.
But I think they also failed because on some level, California voters don't like being bought. The idea that someone is so rich that he or she can spend around $50 million to get elected governor is kind of appaling, particularly in an era when people aren't so happy with the very rich.
Calbuzz had a little fun looking at all the things Meg Whitman could buy  with the $40 million she's already spent (Madonna's apartment, Conan O'Brien's silence, a Cape Cod wastewater plant), but really: You have to wonder what she could have done for society if she'd used that cash for something other than her vanity campaign.
I have no polling data on why mega-millionaires don't win; the current polls show Meg's ahead of Jerry Brown . But I'm not sure her cash and her obscene spending won't become a negative at some point.