For most of the recent Los Angeles area fires there was never any possibility of conducting controlled burns. The terrain is too steep and there were too many structures nearby. A controlled burn could have turned uncontrolled in moments (which has happened before).

Brush clearing can help to an extent. But that's tremendously labor intensive on steep hillsides where heavy equipment can't be used. Taken too far it can also destabilize the soil and cause mudslides during the rainy season.

More realistic solutions are going to include tightening up the building code to make structures more fire resistant, prohibiting building at all in certain risky areas, and provisioning more water supplies so that the hydrants don't run dry.