California politics is driven by media buys. The Greens don't have the kind of cash that Democrats and Republicans have, so they can't compete in the expensive California media market.
If the Greens got enough money to buy time for some paid political ads on TV, the calculus in the gubernatorial race would change. Davis is not popular in his own party, and the purists of the Left would happily vote Green if the party could get some exposure.
In a two-way race, Simon is a goner. In a three-way race with a viable Green candidate, Simon needs less than 50% to win. Every vote that goes to the Greens is a vote Davis doesn't get.
Unfortunately, the Republicans don't have enough cash to fund a Green media campaign to undermine Davis. My solution: FReepers should give money to the Green Party to make it competitive. That's the only way Simon can win this thing.