If California allow Apple and other companies to step in, take control and solve the various crises, that is a vast step backward for democracy as you loose your ability to hold the those with power accountable. For now companies are aiming to fix housing, fairly benign but in the future will they attempt to tackle education? Crime? Even without jumping straight to private police forces run by companies without accountability, think about how a large donation of grant could influence the police force.
I have read stories of how Steve Jobs was an asshole and blocked handicap parking spaces because he wanted to and the reaction by the authorities was that he brings in jobs so it was acceptable. Even if the story is false it show the power the companies already wield in the area and it can be abused even further.
I for one do NOT welcome corporate overlords.