California totally dominates the fruit market. Georgia might call itself the Peach State but California produces 20 times more peaches. California produces 90% of the nation's grapes and twenty times more wine than the second-place state. It's not necessarily that you couldn't grow these elsewhere, but it is a path-dependent process by which government subsidies have pushed all this production to California and killed the industries elsewhere. Changing this so fruits and vegetables are widely produced in every state would involve an abrupt discontinuity that entrenched California growers are sure to oppose.