I can’t speak to the details in California, but in my area controlled burns are done on the remaining prairie areas. They have to be scheduled with care, can be cancelled if the weather conditions make the burns harder to control, and every couple of years one gets away and results in a bigger fire than planned - and that’s in MUCH wetter Indiana.
The fact is that the landscape in California is dry a good part of the year and subject to regular fires and that is the natural state of the landscape. There are plants that require burning - lodgepole pine and eucalyptus encased their seeds, and those casing require burning before the seeds can germinate. There are other plants whose seeds and remain germinated for years in the soil until the chemicals generated by burning vegetation signal them to sprout. California is full of such “pyrophytic” plants, which indicates that the landscape burns so frequently that adapting to require fire is a viable evolutionary path. Since some of these pyrophytic species - such as pines and eucalyptus - are full of resins that burn very nicely doing a controlled burn is a bit tricky, especially when combined with regular lack of rain. Some species of eucalyptus shed their bark, piling up flammable bits at their base over time. It’s like these plants want to be set on fire.
Even if you do perform controlled burns in rural/wilderness areas, doing them in suburbia is more of an issue as the average home owner is reluctant to allow crews to start fires in their backyard for some reason. Poor vegetation management around inhabited areas is a problem. People want “landscaping” with trees and bushes near the house, even if in California the safer thing is to clear a firebreak all around buildings. That means no bushes, no trees, nothing up close to the house. It also is safer to build with stone and concrete and tiles rather that wooden exteriors but people don’t listen and they wind up with a building made out of fire-fuel sitting, during the dry season, in a nest of tinder. Even with perfectly managed forests this will continue to be a problem in California.