Markets exist within politics as much as they do for physical goods. Single-party governments tend to function poorly, regardless of the party, because there's no competition to try and capture the most swing voters, so bad ideas prevail.

California's state government is basically the Comcast of governments. There's no consequences to any of their actions, so their spending goes up and the quality goes down, and will continue to do so, as long as the monopoly is in place.